chore: initial commit

2024-12-11 21:13:00 +01:00 · 2023-01-05 19:28:05 +01:00 · 2023-01-05 19:28:05 +01:00 · 0fa82c5772
commit 0fa82c5772
46 changed files with 2537 additions and 0 deletions
--- a/.clang-format
+++ b/.clang-format
@ -0,0 +1,2 @@
+BasedOnStyle: 'Google'
+ColumnLimit: 0
--- a/.gitignore
+++ b/.gitignore
@ -0,0 +1,7 @@
+build
+bin
+.vscode
+*.out
+*.o
+*.exe
+*.a
--- a/21
+++ b/21
@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) Divlo
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
--- a/37
+++ b/37
@ -0,0 +1,37 @@
+LIBRARY_NAME = libcproject
+CC = gcc
+CC_FLAGS = -Wall -Wextra -Wfloat-equal -Wundef -Werror -std=c17 -pedantic -pedantic-errors -I./
+LIB_CC_FLAGS = -L. -l:./build/${LIBRARY_NAME}.a
+LIB_SOURCES = $(wildcard lib/*.c)
+TEST_SOURCES = $(wildcard test/*.c)
+HEADER_FILES = $(wildcard lib/*.h) $(wildcard test/*.h) ./${LIBRARY_NAME}.h
+MAIN_EXECUTABLE = bin/main.exe
+TEST_EXECUTABLE = bin/test.exe
+
+.PHONY: all
+all: ${LIB_SOURCES}
+	mkdir --parents ./build
+	${CC} ${CC_FLAGS} -c ${LIB_SOURCES}
+	rm --force ./build/${LIBRARY_NAME}.a
+	ar -rcs ./build/${LIBRARY_NAME}.a *.o
+	rm --recursive --force *.o
+
+.PHONY: run
+run: all ./main.c
+	mkdir --parents ./bin
+	${CC} ${CC_FLAGS} -o ${MAIN_EXECUTABLE} ./main.c ${LIB_CC_FLAGS}
+	./${MAIN_EXECUTABLE} ${ARGS}
+
+.PHONY: test
+test: all	 ${TEST_SOURCES}
+	mkdir --parents ./bin
+	${CC} ${CC_FLAGS} -o ${TEST_EXECUTABLE} ${TEST_SOURCES} ${LIB_CC_FLAGS}
+	./${TEST_EXECUTABLE}
+
+.PHONY: lint
+lint:
+	clang-format --Werror --dry-run ${LIB_SOURCES} ${TEST_SOURCES} ${HEADER_FILES} ./main.c
+
+.PHONY: clean
+clean:
+	rm --recursive --force ./build ./bin *.out *.o *.exe *.a
--- a/README.md
+++ b/README.md
@ -0,0 +1,83 @@
+# libcproject
+
+## About
+
+`libcproject` is a C static library for learning purposes. It tries to implement useful functions/data structures while being easier to use than `libc` (C standard library) as much as possible.
+
+## Prerequisites
+
+- [GNU coreutils](https://www.gnu.org/software/coreutils/)
+- [GNU binutils](https://www.gnu.org/software/binutils/)
+- [GNU gcc](https://gcc.gnu.org/)
+- [GNU make](https://www.gnu.org/software/make/)
+- [clang-format](https://clang.llvm.org/docs/ClangFormat.html)
+
+For example on GNU/Linux Ubuntu:
+
+```sh
+sudo apt-get install build-essential gcc make clang-format
+```
+
+## Usage
+
+Steps to create a new C project that uses `libcproject`:
+
+### Step 1: Compile `libcproject`
+
+```sh
+make
+```
+
+### Step 2: Create a new project
+
+```sh
+mkdir my-project
+cd my-project
+```
+
+### Step 3: Install `libcproject` in the project
+
+```sh
+mkdir libcproject
+cp --recursive <path-to-libcproject> ./ # copy
+# or
+ln -s <path-to-libcproject> ./ # symbolic link
+```
+
+### Step 4: Create a new C file
+
+```sh
+touch main.c
+```
+
+```cpp
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "libcproject/libcproject.h"
+
+int main() {
+  char* string = "Hello, world!";
+  printf("%s\n", string);
+  printf("string_length = %ld\n", string_get_length(string)); // `string_get_length` is a function from `libcproject`
+  return EXIT_SUCCESS;
+}
+```
+
+### Step 5: Compile your project and link it with the library
+
+```sh
+gcc -o ./main.exe ./main.c -L. -l:./libcproject/build/libcproject.a
+```
+
+## Contributing
+
+```sh
+make # to compile
+make run # to run main
+make test # to run unit tests
+make lint # to lint the code
+make clean # to clean up
+
+nm ./build/libcproject.a # to see the symbols
+```
--- a/lib/character.c
+++ b/lib/character.c
@ -0,0 +1,47 @@
+#include "character.h"
+
+#include <stdbool.h>
+#include <stdlib.h>
+
+#include "string.h"
+
+void character_append(char* string, const char character) {
+  size_t length = string_get_length(string);
+  character_append_at(string, character, length);
+}
+
+void character_append_at(char* string, const char character, const size_t index) {
+  size_t length = string_get_length(string);
+  for (size_t index_string = length; index_string > index; index_string--) {
+    string[index_string] = string[index_string - 1];
+  }
+  string[index] = character;
+  string[length + 1] = '\0';
+}
+
+char character_to_upper(const char character) {
+  if (character >= 'a' && character <= 'z') {
+    return character + ('A' - 'a');
+  }
+  return character;
+}
+
+char character_to_lower(const char character) {
+  if (character >= 'A' && character <= 'Z') {
+    return character - ('A' - 'a');
+  }
+  return character;
+}
+
+bool character_get_is_digit(const char character) {
+  return character >= '0' && character <= '9';
+}
+
+unsigned char character_get_alphabet_position(const char character) {
+  const char letter = character_to_lower(character);
+  unsigned char position = 0;
+  if (letter >= 'a' && letter <= 'z') {
+    position = (letter - 'a') + 1;
+  }
+  return position;
+}
--- a/lib/character.h
+++ b/lib/character.h
@ -0,0 +1,59 @@
+#ifndef __CHARACTER__
+#define __CHARACTER__
+
+#include <stdbool.h>
+#include <stdlib.h>
+
+/**
+ * @brief Append a character to a string, assuming string points to an array
+ * with enough space.
+ *
+ * @param string
+ * @param character
+ */
+void character_append(char* string, char character);
+
+/**
+ * @brief Append a character to a string at a specific index, assuming string points to an array with enough space.
+ *
+ * @param string
+ * @param character
+ * @param index
+ */
+void character_append_at(char* string, const char character, const size_t index);
+
+/**
+ * @brief Converts the character to uppercase.
+ *
+ * @param character
+ * @return const char
+ */
+char character_to_upper(const char character);
+
+/**
+ * @brief Converts the character to lowercase.
+ *
+ * @param character
+ * @return const char
+ */
+char character_to_lower(const char character);
+
+/**
+ * @brief Check if the character is a digit ('0', '1', '2', '3', '4', '5', '6', '7, '8' or '9').
+ *
+ * @param string1
+ * @param string2
+ * @return true if the character is a digit, false otherwise
+ */
+bool character_get_is_digit(const char character);
+
+/**
+ * @brief Get the position in latin alphabet of the letter (case-insensitive) from 1 to 26.
+ * Return 0 if the character is not a letter.
+ *
+ * @param character
+ * @return char
+ */
+unsigned char character_get_alphabet_position(const char character);
+
+#endif
--- a/lib/convert.c
+++ b/lib/convert.c
@ -0,0 +1,109 @@
+#include "convert.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "character.h"
+#include "mathematics.h"
+#include "stdbool.h"
+#include "string.h"
+
+char* convert_character_to_string(const char character) {
+  char* string = malloc(sizeof(char*) * 2);
+  if (string == NULL) {
+    exit(EXIT_FAILURE);
+  }
+  character_append(string, character);
+  return string;
+}
+
+char convert_character_to_digit(const char character) {
+  return character - '0';
+}
+
+char convert_digit_to_character(const char digit) {
+  return digit + '0';
+}
+
+long long convert_string_to_number(const char* string) {
+  bool is_negative = string[0] == '-';
+  long long integer = 0;
+  size_t length = string_get_length(string);
+  for (size_t index = is_negative ? 1 : 0; index < length; index++) {
+    integer = integer * 10 + convert_character_to_digit(string[index]);
+  }
+  return is_negative ? integer * -1 : integer;
+}
+
+char* convert_number_to_string(const long long integer) {
+  if (integer == 0) {
+    return convert_character_to_string('0');
+  }
+  bool is_negative = integer < 0;
+  size_t length = 1;
+  char* string = malloc(sizeof(char*) * length);
+  if (string == NULL) {
+    exit(EXIT_FAILURE);
+  }
+  long long current = mathematics_absolute_value(integer);
+  while (current != 0) {
+    character_append(string, convert_digit_to_character(current % 10));
+    current = current / 10;
+    length++;
+    string = realloc(string, sizeof(char*) * length);
+  }
+  if (is_negative) {
+    character_append(string, '-');
+    length++;
+    string = realloc(string, sizeof(char*) * length);
+  }
+  return string_reverse(string);
+}
+
+char* convert_number_from_base_10_to_base(unsigned long long number, unsigned int base) {
+  if (number == 0) {
+    return "0";
+  }
+  int remainders[64];
+  int index = 0;
+  while (number > 0) {
+    remainders[index] = number % base;
+    number = number / base;
+    index++;
+  }
+  char* result = malloc(sizeof(char) * (index + 1));
+  int index_result = 0;
+  for (int iteration = index - 1; iteration >= 0; iteration--) {
+    int remainder = remainders[iteration];
+    if (remainder >= 10) {
+      result[index_result] = (char)((remainder - 10) + 'A');
+    } else {
+      result[index_result] = (char)(remainder + '0');
+    }
+    index_result++;
+  }
+  return result;
+}
+
+int convert_number_from_base_to_base_10(char* number, unsigned int base) {
+  int length = string_get_length(number);
+  int exponent = length - 1;
+  int result = 0;
+  int index = 0;
+  while (exponent >= 0) {
+    int current_number = (int)(number[index] - '0');
+    if (current_number >= 10) {
+      current_number = (int)(number[index] - 'A') + 10;
+    } else {
+      current_number = (int)(number[index] - '0');
+    }
+    result = result + current_number * mathematics_pow(base, exponent);
+    exponent--;
+    index++;
+  }
+  return result;
+}
+
+char* convert_number_from_base_to_another(char* number, int base_from, int base_target) {
+  return convert_number_from_base_10_to_base(convert_number_from_base_to_base_10(number, base_from), base_target);
+}
--- a/lib/convert.h
+++ b/lib/convert.h
@ -0,0 +1,20 @@
+#ifndef __CONVERT__
+#define __CONVERT__
+
+char* convert_character_to_string(const char character);
+
+char convert_character_to_digit(const char character);
+
+char convert_digit_to_character(const char digit);
+
+long long convert_string_to_number(const char* string);
+
+char* convert_number_to_string(const long long integer);
+
+char* convert_number_from_base_10_to_base(unsigned long long number, unsigned int base);
+
+int convert_number_from_base_to_base_10(char* number, unsigned int base);
+
+char* convert_number_from_base_to_another(char* number, int base_from, int base_target);
+
+#endif
--- a/lib/dictionary.c
+++ b/lib/dictionary.c
@ -0,0 +1,68 @@
+#include "dictionary.h"
+
+#include <stdlib.h>
+
+#include "string.h"
+
+struct dictionary *dictionary_initialization() {
+  struct dictionary *dictionary = malloc(sizeof(struct dictionary));
+  dictionary->items = malloc(sizeof(struct dictionary_item *) * DICTIONARY_INITIAL_CAPACITY);
+  dictionary->length = 0;
+  dictionary->capacity = DICTIONARY_INITIAL_CAPACITY;
+  for (size_t index = 0; index < dictionary->capacity; index++) {
+    dictionary->items[index] = NULL;
+  }
+  return dictionary;
+}
+
+void dictionary_add(struct dictionary *dictionary, char *key, void *data) {
+  if (dictionary->length == dictionary->capacity) {
+    size_t previous_capacity = dictionary->capacity;
+    dictionary->capacity += DICTIONARY_INITIAL_CAPACITY;
+    dictionary->items = realloc(dictionary->items, sizeof(struct dictionary_item *) * dictionary->capacity);
+    for (size_t index = previous_capacity; index < dictionary->capacity; index++) {
+      dictionary->items[index] = NULL;
+    }
+  }
+  struct dictionary_item *item = NULL;
+  for (size_t index = 0; index < dictionary->length && item == NULL; index++) {
+    if (string_get_is_equal(key, dictionary->items[index]->key)) {
+      item = dictionary->items[index];
+    }
+  }
+  if (item == NULL) {
+    item = malloc(sizeof(struct dictionary_item));
+    item->key = key;
+    item->data = data;
+    dictionary->items[dictionary->length] = item;
+    dictionary->length++;
+  } else {
+    item->data = data;
+  }
+}
+
+void dictionary_remove(struct dictionary *dictionary, char *key) {
+  bool found = false;
+  for (size_t index = 0; index < dictionary->length && !found; index++) {
+    if (string_get_is_equal(key, dictionary->items[index]->key)) {
+      free(dictionary->items[index]);
+      dictionary->items[index] = dictionary->items[dictionary->length - 1];
+      dictionary->length--;
+      found = true;
+    }
+  }
+}
+
+struct dictionary_item *dictionary_get(struct dictionary *dictionary, char *key) {
+  for (size_t index = 0; index < dictionary->length; index++) {
+    struct dictionary_item *item = dictionary->items[index];
+    if (string_get_is_equal(key, item->key)) {
+      return item;
+    }
+  }
+  return NULL;
+}
+
+bool dictionary_contains_key(struct dictionary *dictionary, char *key) {
+  return dictionary_get(dictionary, key) != NULL;
+}
--- a/lib/dictionary.h
+++ b/lib/dictionary.h
@ -0,0 +1,34 @@
+#ifndef __DICTIONARY__
+#define __DICTIONARY__
+
+#include <stdbool.h>
+#include <stdlib.h>
+
+#include "linked_list.h"
+
+#define DICTIONARY_INITIAL_CAPACITY 10
+
+// Dictionary implementation with O(n) lookup complexity.
+struct dictionary {
+  struct dictionary_item **items;
+
+  size_t length;
+  size_t capacity;
+};
+
+struct dictionary_item {
+  void *data;
+  char *key;
+};
+
+struct dictionary *dictionary_initialization();
+
+void dictionary_add(struct dictionary *dictionary, char *key, void *data);
+
+void dictionary_remove(struct dictionary *dictionary, char *key);
+
+struct dictionary_item *dictionary_get(struct dictionary *dictionary, char *key);
+
+bool dictionary_contains_key(struct dictionary *dictionary, char *key);
+
+#endif
--- a/lib/filesystem.c
+++ b/lib/filesystem.c
@ -0,0 +1,57 @@
+#include "filesystem.h"
+
+#include <dirent.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <pwd.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#include "string.h"
+
+int filesystem_read(char *path, char **file_content, off_t *file_size) {
+  int file_descriptor = open(path, O_RDONLY);
+  if (file_descriptor == -1) {
+    return -1;
+  }
+  (*file_size) = lseek(file_descriptor, 0, SEEK_END);
+  lseek(file_descriptor, 0, SEEK_SET);
+  (*file_content) = malloc(*file_size);
+  read(file_descriptor, *file_content, *file_size);
+  close(file_descriptor);
+  return 0;
+}
+
+int filesystem_write(char *path, char *file_content, off_t file_size) {
+  int file_descriptor = open(path, O_WRONLY | O_CREAT | O_TRUNC, 0644);
+  if (file_descriptor == -1) {
+    return -1;
+  }
+  write(file_descriptor, file_content, file_size);
+  close(file_descriptor);
+  return 0;
+}
+
+char *filesystem_get_mimetype(char *path) {
+  if (string_ends_with(path, ".html")) {
+    return "text/html";
+  }
+  if (string_ends_with(path, ".css")) {
+    return "text/css";
+  }
+  if (string_ends_with(path, ".js")) {
+    return "text/javascript";
+  }
+  if (string_ends_with(path, ".png")) {
+    return "image/png";
+  }
+  if (string_ends_with(path, ".jpg") || string_ends_with(path, ".jpeg")) {
+    return "image/jpeg";
+  }
+  if (string_ends_with(path, ".gif")) {
+    return "image/gif";
+  }
+  return "text/plain";
+}
--- a/lib/filesystem.h
+++ b/lib/filesystem.h
@ -0,0 +1,38 @@
+#ifndef __FILESYSTEM__
+#define __FILESYSTEM__
+
+#include <fcntl.h>
+
+/**
+ * @brief Read the content of a file.
+ *
+ * @param path
+ * @param file_content
+ * @param file_size
+ * @return int
+ * @retval -1 if the file does not exist
+ * @retval 0 for success
+ */
+int filesystem_read(char *path, char **file_content, off_t *file_size);
+
+/**
+ * @brief Write the content to a file.
+ *
+ * @param path
+ * @param file_content
+ * @param file_size
+ * @return int
+ * @retval -1 if errors
+ * @retval 0 for success
+ */
+int filesystem_write(char *path, char *file_content, off_t file_size);
+
+/**
+ * @brief Get the mimetype of a file.
+ *
+ * @param path
+ * @return char*
+ */
+char *filesystem_get_mimetype(char *path);
+
+#endif
--- a/lib/linked_list.c
+++ b/lib/linked_list.c
@ -0,0 +1,91 @@
+#include "linked_list.h"
+
+#include <stdbool.h>
+#include <stdlib.h>
+
+#include "stack.h"
+
+struct linked_list *linked_list_initialization() {
+  struct linked_list *list = malloc(sizeof(*list));
+  if (list == NULL) {
+    exit(EXIT_FAILURE);
+  }
+  list->head = NULL;
+  list->length = 0;
+  return list;
+}
+
+struct linked_list_node *linked_list_add_in_head(struct linked_list *list, void *new_data) {
+  struct linked_list_node *node_new = malloc(sizeof(*node_new));
+  if (list == NULL || node_new == NULL) {
+    exit(EXIT_FAILURE);
+  }
+  node_new->data = new_data;
+  node_new->next = list->head;
+  list->head = node_new;
+  list->length = list->length + 1;
+  return node_new;
+}
+
+void linked_list_delete_in_head(struct linked_list *list) {
+  if (list == NULL) {
+    exit(EXIT_FAILURE);
+  }
+  if (list->head != NULL) {
+    struct linked_list_node *node_to_remove = list->head;
+    list->head = list->head->next;
+    list->length = list->length - 1;
+    free(node_to_remove);
+  }
+}
+
+struct linked_list_node *linked_list_add_after_last(struct linked_list *list, void *new_data) {
+  if (list->head == NULL) {
+    return linked_list_add_in_head(list, new_data);
+  }
+  struct linked_list_node *node_new = malloc(sizeof(*node_new));
+  if (list == NULL || node_new == NULL) {
+    exit(EXIT_FAILURE);
+  }
+  node_new->data = new_data;
+  node_new->next = NULL;
+  struct linked_list_node *node_current_last = list->head;
+  size_t index = 0;
+  while (index < list->length - 1) {
+    node_current_last = node_current_last->next;
+    index++;
+  }
+  node_current_last->next = node_new;
+  list->length = list->length + 1;
+  return node_new;
+}
+
+struct linked_list *linked_list_reverse(struct linked_list *list) {
+  struct stack *stack = stack_initialization();
+  struct linked_list_node *linked_list_node_current = list->head;
+  while (linked_list_node_current != NULL) {
+    stack_push(stack, linked_list_node_current->data);
+    linked_list_node_current = linked_list_node_current->next;
+  }
+  struct linked_list *linked_list_reversed = linked_list_initialization();
+  struct stack_node *stack_node_current = stack->first;
+  while (stack_node_current != NULL) {
+    linked_list_add_after_last(linked_list_reversed, stack_node_current->data);
+    stack_node_current = stack_node_current->next;
+  }
+  return linked_list_reversed;
+}
+
+void linked_list_reverse_mutate(struct linked_list *list) {
+  struct linked_list_node **current = &list->head;
+  struct linked_list_node *previous = NULL;
+  while (true) {
+    struct linked_list_node *temporary_current = (*current)->next;
+    (*current)->next = previous;
+    previous = *current;
+    if (temporary_current == NULL) {
+      break;
+    }
+    (*current) = temporary_current;
+  }
+}
--- a/lib/linked_list.h
+++ b/lib/linked_list.h
@ -0,0 +1,30 @@
+#ifndef __LINKED_LIST__
+#define __LINKED_LIST__
+
+#include <stdlib.h>
+
+struct linked_list {
+  // first node of the list
+  struct linked_list_node *head;
+
+  size_t length;
+};
+
+struct linked_list_node {
+  void *data;
+  struct linked_list_node *next;
+};
+
+struct linked_list *linked_list_initialization();
+
+struct linked_list_node *linked_list_add_in_head(struct linked_list *list, void *new_value);
+
+void linked_list_delete_in_head(struct linked_list *list);
+
+struct linked_list_node *linked_list_add_after_last(struct linked_list *list, void *new_data);
+
+struct linked_list *linked_list_reverse(struct linked_list *list);
+
+void linked_list_reverse_mutate(struct linked_list *list);
+
+#endif
--- a/lib/mathematics.c
+++ b/lib/mathematics.c
@ -0,0 +1,36 @@
+#include "mathematics.h"
+
+#include <stdbool.h>
+
+bool mathematics_get_is_equal(const float number1, const float number2) {
+  return (number1 - number2) < MATHEMATICS_FLOAT_PRECISION;
+}
+
+unsigned long long mathematics_absolute_value(const long long number) {
+  if (number >= 0) {
+    return number;
+  }
+  return -number;
+}
+
+unsigned long long mathematics_pow(unsigned long long base, unsigned long long exponent) {
+  return exponent == 0 ? 1 : base * mathematics_pow(base, exponent - 1);
+}
+
+float mathematics_root(float number, unsigned int nth_root) {
+  float result = number;
+  float previous_result = 0;
+  while (!mathematics_get_is_equal(result, previous_result)) {
+    result = (((nth_root - 1) * previous_result) + (number / mathematics_pow(result, nth_root - 1))) / nth_root;
+    previous_result = result;
+  }
+  return result;
+}
+
+float mathematics_square_root(float number) {
+  return mathematics_root(number, 2);
+}
+
+unsigned long long mathematics_factorial(unsigned long long number) {
+  return number == 0 ? 1 : number * mathematics_factorial(number - 1);
+}
--- a/lib/mathematics.h
+++ b/lib/mathematics.h
@ -0,0 +1,27 @@
+#ifndef __MATHEMATICS__
+#define __MATHEMATICS__
+
+#define MATHEMATICS_FLOAT_PRECISION 0.00000001
+
+#include <stdbool.h>
+
+bool mathematics_get_is_equal(const float number1, const float number2);
+
+unsigned long long mathematics_absolute_value(const long long number);
+
+unsigned long long mathematics_pow(unsigned long long base, unsigned long long exponent);
+
+/**
+ * @brief Calculates the nth root of a number using Heron's method.
+ *
+ * @param number
+ * @param nth_root
+ * @return float
+ */
+float mathematics_root(float number, unsigned int nth_root);
+
+float mathematics_square_root(float number);
+
+unsigned long long mathematics_factorial(unsigned long long number);
+
+#endif
--- a/lib/queue.c
+++ b/lib/queue.c
@ -0,0 +1,48 @@
+#include "queue.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+
+struct queue *queue_initialization() {
+  struct queue *queue = malloc(sizeof(*queue));
+  if (queue == NULL) {
+    exit(EXIT_FAILURE);
+  }
+  queue->first = NULL;
+  queue->length = 0;
+  return queue;
+}
+
+void queue_push(struct queue *queue, void *data) {
+  struct queue_node *node_new = malloc(sizeof(*node_new));
+  if (queue == NULL || node_new == NULL) {
+    exit(EXIT_FAILURE);
+  }
+  node_new->data = data;
+  node_new->next = NULL;
+  if (queue->first != NULL) {
+    struct queue_node *node_current = queue->first;
+    while (node_current->next != NULL) {
+      node_current = node_current->next;
+    }
+    node_current->next = node_new;
+  } else {
+    queue->first = node_new;
+  }
+  queue->length = queue->length + 1;
+}
+
+void *queue_pop(struct queue *queue) {
+  if (queue == NULL) {
+    exit(EXIT_FAILURE);
+  }
+  struct queue_node *node = queue->first;
+  void *data = NULL;
+  if (node != NULL) {
+    queue->first = node->next;
+    data = node->data;
+    free(node);
+  }
+  queue->length = queue->length - 1;
+  return data;
+}
--- a/lib/queue.h
+++ b/lib/queue.h
@ -0,0 +1,23 @@
+#ifndef __QUEUE__
+#define __QUEUE__
+
+#include <stdlib.h>
+
+// FIFO = First In First Out
+struct queue {
+  struct queue_node *first;
+  size_t length;
+};
+
+struct queue_node {
+  void *data;
+  struct queue_node *next;
+};
+
+struct queue *queue_initialization();
+
+void queue_push(struct queue *queue, void *data);
+
+void *queue_pop(struct queue *queue);
+
+#endif
--- a/lib/stack.c
+++ b/lib/stack.c
@ -0,0 +1,40 @@
+#include "stack.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+
+struct stack *stack_initialization() {
+  struct stack *stack = malloc(sizeof(*stack));
+  if (stack == NULL) {
+    exit(EXIT_FAILURE);
+  }
+  stack->first = NULL;
+  stack->length = 0;
+  return stack;
+}
+
+void stack_push(struct stack *stack, void *data) {
+  struct stack_node *node_new = malloc(sizeof(*node_new));
+  if (stack == NULL || data == NULL) {
+    exit(EXIT_FAILURE);
+  }
+  node_new->data = data;
+  node_new->next = stack->first;
+  stack->first = node_new;
+  stack->length = stack->length + 1;
+}
+
+void *stack_pop(struct stack *stack) {
+  if (stack == NULL) {
+    exit(EXIT_FAILURE);
+  }
+  struct stack_node *node = stack->first;
+  void *data = NULL;
+  if (node != NULL) {
+    stack->first = node->next;
+    data = node->data;
+    free(node);
+  }
+  stack->length = stack->length - 1;
+  return data;
+}
--- a/lib/stack.h
+++ b/lib/stack.h
@ -0,0 +1,23 @@
+#ifndef __STACK__
+#define __STACK__
+
+#include <stdlib.h>
+
+// LIFO = Last In First Out
+struct stack {
+  struct stack_node *first;
+  size_t length;
+};
+
+struct stack_node {
+  void *data;
+  struct stack_node *next;
+};
+
+struct stack *stack_initialization();
+
+void stack_push(struct stack *stack, void *data);
+
+void *stack_pop(struct stack *stack);
+
+#endif
--- a/lib/string.c
+++ b/lib/string.c
@ -0,0 +1,363 @@
+#include "string.h"
+
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "character.h"
+#include "convert.h"
+#include "dictionary.h"
+
+size_t string_get_length(const char* string) {
+  size_t length = 0;
+  while (string[length] != '\0') {
+    length++;
+  }
+  return length;
+}
+
+char* string_to_uppercase(char* string) {
+  size_t string_length = string_get_length(string);
+  char* result = malloc(sizeof(char*) * string_length);
+  if (result == NULL) {
+    exit(EXIT_FAILURE);
+  }
+  for (size_t index = 0; index < string_length; index++) {
+    character_append(result, character_to_upper(string[index]));
+  }
+  return result;
+}
+
+char* string_to_lowercase(char* string) {
+  size_t string_length = string_get_length(string);
+  char* result = malloc(sizeof(char*) * string_length);
+  if (result == NULL) {
+    exit(EXIT_FAILURE);
+  }
+  for (size_t index = 0; index < string_length; index++) {
+    character_append(result, character_to_lower(string[index]));
+  }
+  return result;
+}
+
+char* string_replace(char* string, char search, char replace) {
+  size_t string_length = string_get_length(string);
+  char* result = malloc(sizeof(char*) * string_length);
+  if (result == NULL) {
+    exit(EXIT_FAILURE);
+  }
+  for (size_t index = 0; index < string_length; index++) {
+    bool is_search_value = search == string[index];
+    if (is_search_value) {
+      character_append(result, replace);
+    } else {
+      character_append(result, string[index]);
+    }
+  }
+  return result;
+}
+
+char* string_trim_start(char* string) {
+  size_t string_length = string_get_length(string);
+  char* result = malloc(sizeof(char*) * string_length);
+  if (result == NULL) {
+    exit(EXIT_FAILURE);
+  }
+  size_t index_space = 0;
+  while (string[index_space] == ' ') {
+    index_space++;
+  }
+  for (size_t index = index_space; index < string_length; index++) {
+    character_append(result, string[index]);
+  }
+  return result;
+}
+
+char* string_trim_end(char* string) {
+  size_t string_length = string_get_length(string);
+  char* result = malloc(sizeof(char*) * string_length);
+  if (result == NULL) {
+    exit(EXIT_FAILURE);
+  }
+  size_t index_space = string_length - 1;
+  while (string[index_space] == ' ') {
+    index_space--;
+  }
+  for (size_t index = 0; index < index_space + 1; index++) {
+    character_append(result, string[index]);
+  }
+  return result;
+}
+
+char* string_trim(char* string) {
+  char* result = string_trim_start(string);
+  result = string_trim_end(result);
+  return result;
+}
+
+char* string_copy(const char* string) {
+  return string_substring(string, 0, string_get_length(string));
+}
+
+char* string_capitalize(char* string) {
+  size_t string_length = string_get_length(string);
+  char* result = malloc(sizeof(char*) * string_length);
+  if (result == NULL) {
+    exit(EXIT_FAILURE);
+  }
+  for (size_t index = 0; index < string_length; index++) {
+    bool is_first_character = index == 0;
+    if (is_first_character) {
+      character_append(result, character_to_upper(string[index]));
+    } else {
+      character_append(result, string[index]);
+    }
+  }
+  return result;
+}
+
+size_t string_total_occurrences_of_character(char* string, char character) {
+  size_t result = 0;
+  size_t string_length = string_get_length(string);
+  for (size_t index = 0; index < string_length; index++) {
+    char current_character = string[index];
+    if (current_character == character) {
+      result += 1;
+    }
+  }
+  return result;
+}
+
+char* string_reverse(const char* string) {
+  size_t string_length = string_get_length(string);
+  size_t index = 0;
+  char* result = malloc(sizeof(char*) * string_length);
+  if (result == NULL) {
+    exit(EXIT_FAILURE);
+  }
+  for (index = string_length - 1; index > 0; index--) {
+    character_append(result, string[index]);
+  }
+  character_append(result, string[index]);
+  return result;
+}
+
+bool string_get_is_equal(const char* string1, const char* string2) {
+  size_t string1_length = string_get_length(string1);
+  size_t string2_length = string_get_length(string2);
+  bool is_equal = string1_length == string2_length;
+  for (size_t index = 0; index < string1_length && is_equal; index++) {
+    if (string1[index] != string2[index]) {
+      is_equal = false;
+    }
+  }
+  return is_equal;
+}
+
+bool string_get_is_integer(const char* string) {
+  size_t index = 0;
+  size_t string_length = string_get_length(string);
+  bool is_integer = string_length >= 1;
+  if (is_integer && string[0] == '-') {
+    if (string_length == 1) {
+      is_integer = false;
+    } else {
+      index++;
+    }
+  }
+  while (index < string_length && is_integer) {
+    if (!character_get_is_digit(string[index])) {
+      is_integer = false;
+    }
+    index++;
+  }
+  return is_integer;
+}
+
+char** string_split(const char* string, char separator, size_t* result_size) {
+  size_t string_length = string_get_length(string);
+  size_t index_string = 0;
+  size_t index_current = 0;
+  size_t index_result = 0;
+  char* current = malloc(sizeof(char*) * string_length);
+  char** result = malloc(sizeof(char**) * index_result);
+  if (result == NULL || current == NULL) {
+    exit(EXIT_FAILURE);
+  }
+  while (index_string < string_length) {
+    if (string[index_string] == separator) {
+      result[index_result] = string_copy(current);
+      index_result++;
+      result = realloc(result, sizeof(char*) * index_result);
+      if (result == NULL) {
+        exit(EXIT_FAILURE);
+      }
+      index_current = 0;
+      current = string_copy("");
+    } else {
+      character_append(current, string[index_string]);
+      index_current++;
+    }
+    index_string++;
+  }
+  result[index_result] = string_copy(current);
+  free(current);
+  *result_size = index_result + 1;
+  return result;
+}
+
+char* string_join(char** array, const char separator, size_t array_length) {
+  size_t string_length = array_length;
+  char* string = malloc(sizeof(char*) * string_length);
+  if (string == NULL) {
+    exit(EXIT_FAILURE);
+  }
+  for (size_t index_array = 0; index_array < array_length; index_array++) {
+    char* substring = array[index_array];
+    size_t substring_length = string_get_length(substring);
+    string_length += substring_length;
+    string = realloc(string, sizeof(char*) * string_length);
+    if (string == NULL) {
+      exit(EXIT_FAILURE);
+    }
+    for (size_t index_substring = 0; index_substring < substring_length; index_substring++) {
+      character_append(string, substring[index_substring]);
+    }
+    bool is_last_character = index_array == (array_length - 1);
+    if (!is_last_character) {
+      character_append(string, separator);
+    }
+  }
+  return string;
+}
+
+char* string_concatenate(char* string1, char* string2) {
+  size_t string1_length = string_get_length(string1);
+  size_t string2_length = string_get_length(string2);
+  size_t result_length = string1_length + string2_length;
+  char* result = malloc(sizeof(char*) * result_length);
+  if (result == NULL) {
+    exit(EXIT_FAILURE);
+  }
+  for (size_t index_string1 = 0; index_string1 < string1_length; index_string1++) {
+    character_append(result, string1[index_string1]);
+  }
+  for (size_t index_string2 = 0; index_string2 < string2_length; index_string2++) {
+    character_append(result, string2[index_string2]);
+  }
+  return result;
+}
+
+bool string_get_has_unique_characters(const char* string) {
+  bool has_unique = true;
+  size_t string_length = string_get_length(string);
+  struct dictionary* characters_already_seen = dictionary_initialization();
+  for (size_t index = 0; index < string_length && has_unique; index++) {
+    char character = string[index];
+    char* key = convert_character_to_string(character);
+    if (dictionary_contains_key(characters_already_seen, key)) {
+      has_unique = false;
+    } else {
+      dictionary_add(characters_already_seen, key, (void*)true);
+    }
+  }
+  return has_unique;
+}
+
+char* string_substring(const char* string, size_t index_start, size_t index_end) {
+  size_t string_length = string_get_length(string);
+  char* result = malloc(sizeof(char*) * string_length);
+  for (size_t index = index_start; index <= index_end; index++) {
+    character_append(result, string[index]);
+  }
+  return result;
+}
+
+bool string_get_is_substring(const char* string, const char* substring) {
+  bool is_substring = false;
+  size_t string_length = string_get_length(string);
+  size_t substring_length = string_get_length(substring);
+  for (size_t index_string = 0; index_string < string_length && !is_substring; index_string++) {
+    size_t index_substring = 0;
+    size_t index_considered = index_string;
+    while (index_substring < substring_length && string[index_considered] == substring[index_substring]) {
+      index_substring++;
+      index_considered++;
+    }
+    is_substring = index_substring == substring_length;
+  }
+  return is_substring;
+}
+
+char* string_get_formatted_number(const long long number, char* separator) {
+  char* number_string = convert_number_to_string(number);
+  bool is_negative = number_string[0] == '-';
+  if (is_negative) {
+    number_string = string_substring(number_string, 1, string_get_length(number_string));
+  }
+  size_t number_string_length = string_get_length(number_string);
+  char* result = malloc(sizeof(char*) * number_string_length);
+  if (result == NULL) {
+    exit(EXIT_FAILURE);
+  }
+  size_t count = 0;
+  for (size_t index = 0; index < number_string_length; index++) {
+    size_t index_reversed = number_string_length - index - 1;
+    count++;
+    result = string_concatenate(result, convert_character_to_string(number_string[index_reversed]));
+    if (count == 3) {
+      result = string_concatenate(result, separator);
+      count = 0;
+    }
+  }
+  result = string_reverse(result);
+  size_t result_length = string_get_length(result);
+  if (result_length % 4 == 0) {
+    result = string_substring(result, 1, result_length);
+  }
+  if (is_negative) {
+    result = string_concatenate(convert_character_to_string('-'), result);
+  }
+  return result;
+}
+
+char* string_get_last_occurence_of_character(const char* string, char character) {
+  size_t string_length = string_get_length(string);
+  char* result = malloc(sizeof(char*) * string_length);
+  if (result == NULL) {
+    exit(EXIT_FAILURE);
+  }
+  size_t index_result = 0;
+  for (size_t index = 0; index < string_length; index++) {
+    if (string[index] == character) {
+      index_result = 0;
+      result = string_copy("");
+    }
+    character_append(result, string[index]);
+    index_result++;
+  }
+  return result;
+}
+
+bool string_starts_with(const char* string, const char* prefix) {
+  bool starts_with = true;
+  size_t prefix_length = string_get_length(prefix);
+  for (size_t index = 0; index < prefix_length && starts_with; index++) {
+    starts_with = string[index] == prefix[index];
+  }
+  return starts_with;
+}
+
+bool string_ends_with(const char* string, const char* prefix) {
+  bool ends_with = true;
+  size_t string_length = string_get_length(string);
+  size_t prefix_length = string_get_length(prefix);
+  size_t index_string = string_length - 1;
+  size_t index_prefix = prefix_length - 1;
+  while (index_prefix > 0 && ends_with) {
+    ends_with = string[index_string] == prefix[index_prefix];
+    index_string--;
+    index_prefix--;
+  }
+  return ends_with;
+}
--- a/lib/string.h
+++ b/lib/string.h
@ -0,0 +1,204 @@
+#ifndef __STRING__
+#define __STRING__
+
+#include <stdbool.h>
+#include <stdlib.h>
+
+/**
+ * @brief Return the length of a string (excluding '\0').
+ *
+ * @param string
+ * @return size_t
+ */
+size_t string_get_length(const char* string);
+
+/**
+ * @brief Converts all the alphabetic characters in a string to uppercase.
+ *
+ * @param string
+ * @return char*
+ */
+char* string_to_uppercase(char* string);
+
+/**
+ * @brief Converts all the alphabetic characters in a string to lowercase.
+ *
+ * @param string
+ * @return char*
+ */
+char* string_to_lowercase(char* string);
+
+/**
+ * @brief Replace all the occurrences of search value into replace value in the string.
+ *
+ * @param string
+ * @param search_value A character search value.
+ * @param replace_value A character containing the text to replace for match.
+ * @return char*
+ */
+char* string_replace(char* string, char search, char replace);
+
+/**
+ * @brief Removes all whitespace from the start of a string.
+ *
+ * @param string
+ * @return char*
+ */
+char* string_trim_start(char* string);
+
+/**
+ * @brief Removes all whitespace from the end of a string.
+ *
+ * @param string
+ * @return char*
+ */
+char* string_trim_end(char* string);
+
+/**
+ * @brief Removes all whitespace from the start and end of a string.
+ *
+ * @param string
+ * @return char*
+ */
+char* string_trim(char* string);
+
+/**
+ * @brief Return the copy of a string.
+ *
+ * @param string
+ * @return char*
+ */
+char* string_copy(const char* string);
+
+/**
+ * @brief Capitalizes the string.
+ *
+ * @param string
+ * @return char*
+ */
+char* string_capitalize(char* string);
+
+/**
+ * @brief Returns the total number of occurrences of the given character in the string.
+ *
+ * @param string
+ * @param character
+ * @return size_t
+ */
+size_t string_total_occurrences_of_character(char* string, char character);
+
+/**
+ * @brief Reverse the characters in an array.
+ *
+ * @param string
+ * @return char*
+ */
+char* string_reverse(const char* string);
+
+/**
+ * @brief Check if two strings are equals.
+ *
+ * @param string1
+ * @param string2
+ * @return true if the strings are equals, false otherwise
+ */
+bool string_get_is_equal(const char* string1, const char* string2);
+
+/**
+ * @brief Check if the string is a integer.
+ *
+ * @param string
+ * @return true if the string is a integer, false otherwise
+ */
+bool string_get_is_integer(const char* string);
+
+/**
+ * @brief Split a string into substrings using the specified separator and return them as an array and update the pointer `result_size` to the resulting size of the created array.
+ *
+ * @param string
+ * @param separator
+ * @return char**
+ */
+char** string_split(const char* string, char separator, size_t* result_size);
+
+/**
+ * @brief Adds all the elements of an array into a string, separated by the specified separator string.
+ *
+ * @param array
+ * @param separator
+ * @return char*
+ */
+char* string_join(char** array, const char separator, size_t array_length);
+
+/**
+ * @brief Concatenate two strings.
+ *
+ * @param string1
+ * @param string2
+ * @return char*
+ */
+char* string_concatenate(char* string1, char* string2);
+
+/**
+ * @brief Check if a string contains only unique characters.
+ *
+ * @param string
+ * @return true if string contains only unique characters, false otherwise
+ */
+bool string_get_has_unique_characters(const char* string);
+
+/**
+ * @brief Returns the part of the string between the start and end indexes (both included).
+ *
+ * @param string
+ * @param index_start
+ * @param index_end
+ * @return char*
+ */
+char* string_substring(const char* string, size_t index_start, size_t index_end);
+
+/**
+ * @brief Check if a string contains a substring.
+ *
+ * @param string
+ * @param substring
+ * @return true if the string contains the substring, false otherwise
+ */
+bool string_get_is_substring(const char* string, const char* substring);
+
+/**
+ * @brief Format a number to a string with specified separator.
+ *
+ * @param integer
+ * @return char* example: string_get_formatted_number(1000, " ") => "1 000"
+ */
+char* string_get_formatted_number(const long long number, char* separator);
+
+/**
+ * @brief Returns a pointer to the last occurrence of character in the string.
+ *
+ * @param string
+ * @param character
+ * @return char*
+ */
+char* string_get_last_occurence_of_character(const char* string, char character);
+
+/**
+ * @brief Check if a string starts with a substring.
+ *
+ * @param string
+ * @param prefix
+ * @return true if the string starts with the substring, false otherwise
+ */
+bool string_starts_with(const char* string, const char* prefix);
+
+/**
+ * @brief Check if a string ends with a substring.
+ *
+ * @param string
+ * @param prefix
+ * @return true if the string ends with the substring, false otherwise
+ */
+bool string_ends_with(const char* string, const char* prefix);
+
+#endif
--- a/lib/terminal.c
+++ b/lib/terminal.c
@ -0,0 +1,122 @@
+#include "terminal.h"
+
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "character.h"
+#include "dictionary.h"
+#include "linked_list.h"
+#include "queue.h"
+#include "stack.h"
+
+char* terminal_input() {
+  char character;
+  size_t length = 1;
+  char* string = malloc(length * sizeof(char));
+  if (string == NULL) {
+    exit(EXIT_FAILURE);
+  }
+  *string = '\0';
+  while ((character = getchar()) != '\n' && character != EOF) {
+    length++;
+    string = realloc(string, length * sizeof(char));
+    if (string == NULL) {
+      exit(EXIT_FAILURE);
+    }
+    character_append(string, character);
+  }
+  return string;
+}
+
+void terminal_print_array(void* array, size_t array_size, size_t element_size, void (*print_element)(void*)) {
+  printf("[");
+  for (size_t index = 0; index < array_size; index++) {
+    void* element = (char*)array + index * element_size;
+    print_element(element);
+    bool is_last = index == array_size - 1;
+    if (!is_last) {
+      printf(", ");
+    }
+  }
+  printf("]\n");
+}
+
+void terminal_print_int(void* value) {
+  printf("%d", *(int*)value);
+}
+
+void terminal_print_long(void* value) {
+  printf("%ld", *(long*)value);
+}
+
+void terminal_print_unsigned_long(void* value) {
+  printf("%lu", *(unsigned long*)value);
+}
+
+void terminal_print_char(void* value) {
+  printf("%c", *(char*)value);
+}
+
+void terminal_print_string(void* value) {
+  printf("%s", (char*)value);
+}
+
+void terminal_print_stack(struct stack* stack, void (*print_element)(void*)) {
+  if (stack == NULL) {
+    exit(EXIT_FAILURE);
+  }
+  struct stack_node* node_current = stack->first;
+  while (node_current != NULL) {
+    printf("|\t");
+    void* element = (char*)node_current->data;
+    print_element(&element);
+    node_current = node_current->next;
+    printf("\t|\n");
+  }
+}
+
+void terminal_print_queue(struct queue* queue, void (*print_element)(void*)) {
+  if (queue == NULL) {
+    exit(EXIT_FAILURE);
+  }
+  struct queue_node* node_current = queue->first;
+  while (node_current != NULL) {
+    printf("|\t");
+    void* element = (char*)node_current->data;
+    print_element(&element);
+    node_current = node_current->next;
+    printf("\t|\n");
+  }
+}
+
+void terminal_print_linked_list(struct linked_list* linked_list, void (*print_element)(void*)) {
+  if (linked_list == NULL) {
+    exit(EXIT_FAILURE);
+  }
+  struct linked_list_node* node_current = linked_list->head;
+  while (node_current != NULL) {
+    void* element = (char*)node_current->data;
+    node_current = node_current->next;
+    print_element(&element);
+    printf(" -> ");
+  }
+  printf("NULL\n");
+}
+
+void terminal_print_dictionary(struct dictionary* dictionary, void (*print_element)(void*)) {
+  if (dictionary == NULL) {
+    exit(EXIT_FAILURE);
+  }
+  printf("{\n");
+  for (size_t index = 0; index < dictionary->length; index++) {
+    struct dictionary_item* item = dictionary->items[index];
+    printf("\t\"");
+    terminal_print_string(item->key);
+    printf("\" -> ");
+    print_element(&item->data);
+    printf("\n");
+  }
+  printf("}\n");
+}
--- a/lib/terminal.h
+++ b/lib/terminal.h
@ -0,0 +1,38 @@
+#ifndef __TERMINAL__
+#define __TERMINAL__
+
+#include <stdlib.h>
+
+#include "dictionary.h"
+#include "linked_list.h"
+#include "queue.h"
+#include "stack.h"
+
+/**
+ * @brief Read a line from stdin.
+ *
+ * @return char*
+ */
+char* terminal_input();
+
+void terminal_print_array(void* array, size_t array_size, size_t element_size, void (*print_element)(void*));
+
+void terminal_print_int(void* value);
+
+void terminal_print_long(void* value);
+
+void terminal_print_unsigned_long(void* value);
+
+void terminal_print_char(void* value);
+
+void terminal_print_string(void* value);
+
+void terminal_print_stack(struct stack* stack, void (*print_element)(void*));
+
+void terminal_print_queue(struct queue* queue, void (*print_element)(void*));
+
+void terminal_print_linked_list(struct linked_list* linked_list, void (*print_element)(void*));
+
+void terminal_print_dictionary(struct dictionary* dictionary, void (*print_element)(void*));
+
+#endif
--- a/libcproject.h
+++ b/libcproject.h
@ -0,0 +1,15 @@
+#ifndef __LIBCPROJECT__
+#define __LIBCPROJECT__
+
+#include "lib/character.h"
+#include "lib/convert.h"
+#include "lib/dictionary.h"
+#include "lib/filesystem.h"
+#include "lib/linked_list.h"
+#include "lib/mathematics.h"
+#include "lib/queue.h"
+#include "lib/stack.h"
+#include "lib/string.h"
+#include "lib/terminal.h"
+
+#endif
--- a/main.c
+++ b/main.c
@ -0,0 +1,11 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "libcproject.h"
+
+int main() {
+  char* string = "Hello, world!";
+  printf("%s\n", string);
+  printf("string_length = %ld\n", string_get_length(string));
+  return EXIT_SUCCESS;
+}
--- a/test/character_test.c
+++ b/test/character_test.c
@ -0,0 +1,73 @@
+#include "character_test.h"
+
+#include <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "libcproject.h"
+#include "test.h"
+
+void character_test() {
+  character_append_test();
+  character_append_at_test();
+  character_to_upper_test();
+  character_to_lower_test();
+  character_get_is_digit_test();
+  character_get_alphabet_position_test();
+}
+
+void character_append_test() {
+  char string[5] = "abc";
+  character_append(string, 'd');
+  assert(assert_string_equal(string, "abcd"));
+}
+
+void character_append_at_test() {
+  char string[5] = "abc";
+  character_append_at(string, 'd', 1);
+  assert(assert_string_equal(string, "adbc"));
+
+  char string2[5] = "abcd";
+  character_append_at(string2, 'e', 4);
+  assert(assert_string_equal(string2, "abcde"));
+}
+
+void character_to_upper_test() {
+  assert(character_to_upper('a') == 'A');
+  assert(character_to_upper('e') == 'E');
+  assert(character_to_upper('A') == 'A');
+}
+
+void character_to_lower_test() {
+  assert(character_to_lower('A') == 'a');
+  assert(character_to_lower('E') == 'e');
+  assert(character_to_lower('a') == 'a');
+}
+
+void character_get_is_digit_test() {
+  assert(character_get_is_digit('0'));
+  assert(character_get_is_digit('1'));
+  assert(character_get_is_digit('2'));
+  assert(character_get_is_digit('3'));
+  assert(character_get_is_digit('4'));
+  assert(character_get_is_digit('5'));
+  assert(character_get_is_digit('6'));
+  assert(character_get_is_digit('7'));
+  assert(character_get_is_digit('8'));
+  assert(character_get_is_digit('9'));
+  assert(!character_get_is_digit('a'));
+  assert(!character_get_is_digit('/'));
+  assert(!character_get_is_digit(':'));
+}
+
+void character_get_alphabet_position_test() {
+  assert(character_get_alphabet_position('a') == 1);
+  assert(character_get_alphabet_position('A') == 1);
+  assert(character_get_alphabet_position('B') == 2);
+  assert(character_get_alphabet_position('D') == 4);
+  assert(character_get_alphabet_position('m') == 13);
+  assert(character_get_alphabet_position('n') == 14);
+  assert(character_get_alphabet_position('z') == 26);
+  assert(character_get_alphabet_position('@') == 0);
+  assert(character_get_alphabet_position('-') == 0);
+}
--- a/test/character_test.h
+++ b/test/character_test.h
@ -0,0 +1,18 @@
+#ifndef __CHARACTER_TEST__
+#define __CHARACTER_TEST__
+
+void character_test();
+
+void character_append_test();
+
+void character_append_at_test();
+
+void character_to_upper_test();
+
+void character_to_lower_test();
+
+void character_get_is_digit_test();
+
+void character_get_alphabet_position_test();
+
+#endif
--- a/test/convert_test.c
+++ b/test/convert_test.c
@ -0,0 +1,102 @@
+#include "convert_test.h"
+
+#include <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "libcproject.h"
+#include "test.h"
+
+void convert_test() {
+  convert_character_to_string_test();
+  convert_character_to_digit_test();
+  convert_digit_to_character_test();
+  convert_string_to_number_test();
+  convert_number_to_string_test();
+  convert_number_from_base_to_another_test();
+}
+
+void convert_character_to_string_test() {
+  assert(assert_string_equal(convert_character_to_string('a'), "a"));
+  assert(assert_string_equal(convert_character_to_string('A'), "A"));
+  assert(assert_string_equal(convert_character_to_string('0'), "0"));
+  assert(assert_string_equal(convert_character_to_string(' '), " "));
+  assert(assert_string_equal(convert_character_to_string('\0'), ""));
+}
+
+void convert_character_to_digit_test() {
+  assert(convert_character_to_digit('0') == 0);
+  assert(convert_character_to_digit('1') == 1);
+  assert(convert_character_to_digit('2') == 2);
+  assert(convert_character_to_digit('3') == 3);
+  assert(convert_character_to_digit('4') == 4);
+  assert(convert_character_to_digit('5') == 5);
+  assert(convert_character_to_digit('6') == 6);
+  assert(convert_character_to_digit('7') == 7);
+  assert(convert_character_to_digit('8') == 8);
+  assert(convert_character_to_digit('9') == 9);
+}
+
+void convert_digit_to_character_test() {
+  assert(convert_digit_to_character(0) == '0');
+  assert(convert_digit_to_character(1) == '1');
+  assert(convert_digit_to_character(2) == '2');
+  assert(convert_digit_to_character(3) == '3');
+  assert(convert_digit_to_character(4) == '4');
+  assert(convert_digit_to_character(5) == '5');
+  assert(convert_digit_to_character(6) == '6');
+  assert(convert_digit_to_character(7) == '7');
+  assert(convert_digit_to_character(8) == '8');
+  assert(convert_digit_to_character(9) == '9');
+}
+
+void convert_string_to_number_test() {
+  assert(convert_string_to_number("0") == 0);
+  assert(convert_string_to_number("1") == 1);
+  assert(convert_string_to_number("2") == 2);
+  assert(convert_string_to_number("3") == 3);
+  assert(convert_string_to_number("4") == 4);
+  assert(convert_string_to_number("5") == 5);
+  assert(convert_string_to_number("6") == 6);
+  assert(convert_string_to_number("7") == 7);
+  assert(convert_string_to_number("8") == 8);
+  assert(convert_string_to_number("9") == 9);
+  assert(convert_string_to_number("10") == 10);
+  assert(convert_string_to_number("11") == 11);
+  assert(convert_string_to_number("20") == 20);
+  assert(convert_string_to_number("-0") == 0);
+  assert(convert_string_to_number("-1") == -1);
+  assert(convert_string_to_number("-20") == -20);
+}
+
+void convert_number_to_string_test() {
+  assert(assert_string_equal(convert_number_to_string(0), "0"));
+  assert(assert_string_equal(convert_number_to_string(1), "1"));
+  assert(assert_string_equal(convert_number_to_string(2), "2"));
+  assert(assert_string_equal(convert_number_to_string(3), "3"));
+  assert(assert_string_equal(convert_number_to_string(4), "4"));
+  assert(assert_string_equal(convert_number_to_string(5), "5"));
+  assert(assert_string_equal(convert_number_to_string(6), "6"));
+  assert(assert_string_equal(convert_number_to_string(7), "7"));
+  assert(assert_string_equal(convert_number_to_string(8), "8"));
+  assert(assert_string_equal(convert_number_to_string(9), "9"));
+  assert(assert_string_equal(convert_number_to_string(10), "10"));
+  assert(assert_string_equal(convert_number_to_string(11), "11"));
+  assert(assert_string_equal(convert_number_to_string(20), "20"));
+  assert(assert_string_equal(convert_number_to_string(-0), "0"));
+  assert(assert_string_equal(convert_number_to_string(-1), "-1"));
+  assert(assert_string_equal(convert_number_to_string(-20), "-20"));
+}
+
+void convert_number_from_base_to_another_test() {
+  assert(assert_string_equal(convert_number_from_base_to_another("15", 10, 16), "F"));
+  assert(assert_string_equal(convert_number_from_base_to_another("100000000", 2, 16), "100"));
+  assert(assert_string_equal(convert_number_from_base_to_another("FFFFFF", 16, 10), "16777215"));
+  assert(assert_string_equal(convert_number_from_base_to_another("1D57", 17, 35), "75C"));
+  assert(assert_string_equal(convert_number_from_base_to_another("80E", 20, 5), "100324"));
+  assert(assert_string_equal(convert_number_from_base_to_another("99", 10, 10), "99"));
+  assert(assert_string_equal(convert_number_from_base_to_another("3433024", 6, 28), "8008"));
+  assert(assert_string_equal(convert_number_from_base_to_another("30288G3A", 17, 36), "KF12OI"));
+  assert(assert_string_equal(convert_number_from_base_to_another("10", 9, 9), "10"));
+  assert(assert_string_equal(convert_number_from_base_to_another("10E", 23, 8), "1037"));
+}
--- a/test/convert_test.h
+++ b/test/convert_test.h
@ -0,0 +1,18 @@
+#ifndef __CONVERT_TEST__
+#define __CONVERT_TEST__
+
+void convert_test();
+
+void convert_character_to_string_test();
+
+void convert_character_to_digit_test();
+
+void convert_digit_to_character_test();
+
+void convert_string_to_number_test();
+
+void convert_number_to_string_test();
+
+void convert_number_from_base_to_another_test();
+
+#endif
--- a/test/dictionary_test.c
+++ b/test/dictionary_test.c
@ -0,0 +1,33 @@
+#include "dictionary_test.h"
+
+#include <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "libcproject.h"
+
+void dictionary_test() {
+  struct dictionary *dictionary = dictionary_initialization();
+  assert(dictionary->length == 0);
+  dictionary_add(dictionary, "key", (void *)'a');
+  dictionary_add(dictionary, "key1", (void *)'b');
+  dictionary_add(dictionary, "key2", (void *)'c');
+  dictionary_add(dictionary, "key3", (void *)'d');
+  dictionary_add(dictionary, "key4", (void *)'e');
+  dictionary_add(dictionary, "key5", (void *)'f');
+  assert(dictionary->length == 6);
+  assert(dictionary_get(dictionary, "key")->data == (void *)'a');
+  assert(dictionary_get(dictionary, "key1")->data == (void *)'b');
+  assert(dictionary_get(dictionary, "key2")->data == (void *)'c');
+  assert(dictionary_get(dictionary, "key3")->data == (void *)'d');
+  assert(dictionary_get(dictionary, "key4")->data == (void *)'e');
+  assert(dictionary_get(dictionary, "key5")->data == (void *)'f');
+  dictionary_add(dictionary, "key5", (void *)'a');
+  assert(dictionary_get(dictionary, "key5")->data == (void *)'a');
+  assert(dictionary_contains_key(dictionary, "key5"));
+  assert(!dictionary_contains_key(dictionary, "invalid key"));
+  assert(dictionary_contains_key(dictionary, "key5"));
+  dictionary_remove(dictionary, "key5");
+  assert(dictionary->length == 5);
+  assert(!dictionary_contains_key(dictionary, "key5"));
+}
--- a/test/dictionary_test.h
+++ b/test/dictionary_test.h
@ -0,0 +1,6 @@
+#ifndef __DICTIONARY_TEST__
+#define __DICTIONARY_TEST__
+
+void dictionary_test();
+
+#endif
--- a/test/linked_list_test.c
+++ b/test/linked_list_test.c
@ -0,0 +1,99 @@
+#include "linked_list_test.h"
+
+#include <assert.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "libcproject.h"
+
+void linked_list_test() {
+  linked_list_initialization_test();
+  linked_list_add_in_head_test();
+  linked_list_delete_in_head_test();
+  linked_list_add_after_last_test();
+  linked_list_reverse_test();
+  linked_list_reverse_mutate_test();
+}
+
+void linked_list_initialization_test() {
+  struct linked_list *list = linked_list_initialization();
+  assert(list->length == 0);
+  assert(list->head == NULL);
+}
+
+void linked_list_add_in_head_test() {
+  struct linked_list *list = linked_list_initialization();
+  linked_list_add_in_head(list, (void *)4);
+  linked_list_add_in_head(list, (void *)8);
+  linked_list_add_in_head(list, (void *)15);
+  assert(list->length == 3);
+  assert(((uintptr_t)list->head->data) == 15);
+  assert(((uintptr_t)list->head->next->data) == 8);
+  assert(((uintptr_t)list->head->next->next->data) == 4);
+  assert(list->head->next->next->next == NULL);
+}
+
+void linked_list_delete_in_head_test() {
+  struct linked_list *list = linked_list_initialization();
+  linked_list_add_in_head(list, (void *)4);
+  linked_list_add_in_head(list, (void *)8);
+  linked_list_add_in_head(list, (void *)15);
+  linked_list_delete_in_head(list);
+  assert(list->length == 2);
+  assert(((uintptr_t)list->head->data) == 8);
+  assert(((uintptr_t)list->head->next->data) == 4);
+  assert(list->head->next->next == NULL);
+}
+
+void linked_list_add_after_last_test() {
+  struct linked_list *list = linked_list_initialization();
+  linked_list_add_in_head(list, (void *)4);
+  linked_list_add_in_head(list, (void *)8);
+  linked_list_add_in_head(list, (void *)15);
+  assert(list->length == 3);
+  assert(((uintptr_t)list->head->data) == 15);
+  assert(((uintptr_t)list->head->next->data) == 8);
+  assert(((uintptr_t)list->head->next->next->data) == 4);
+  linked_list_add_after_last(list, (void *)18);
+  assert(list->length == 4);
+  assert(((uintptr_t)list->head->data) == 15);
+  assert(((uintptr_t)list->head->next->data) == 8);
+  assert(((uintptr_t)list->head->next->next->data) == 4);
+  assert(((uintptr_t)list->head->next->next->next->data) == 18);
+}
+
+void linked_list_reverse_test() {
+  struct linked_list *list = linked_list_initialization();
+  linked_list_add_after_last(list, (void *)'A');
+  linked_list_add_after_last(list, (void *)'B');
+  linked_list_add_after_last(list, (void *)'C');
+  linked_list_add_after_last(list, (void *)'D');
+  assert(list->length == 4);
+  struct linked_list *list_reversed = linked_list_reverse(list);
+  assert(list->length == 4);
+  assert((list->head->data) == (void *)'A');
+  assert((list->head->next->data) == (void *)'B');
+  assert((list->head->next->next->data) == (void *)'C');
+  assert((list->head->next->next->next->data) == (void *)'D');
+  assert(list_reversed->length == 4);
+  assert((list_reversed->head->data) == (void *)'D');
+  assert((list_reversed->head->next->data) == (void *)'C');
+  assert((list_reversed->head->next->next->data) == (void *)'B');
+  assert((list_reversed->head->next->next->next->data) == (void *)'A');
+}
+
+void linked_list_reverse_mutate_test() {
+  struct linked_list *list = linked_list_initialization();
+  linked_list_add_after_last(list, (void *)'A');
+  linked_list_add_after_last(list, (void *)'B');
+  linked_list_add_after_last(list, (void *)'C');
+  linked_list_add_after_last(list, (void *)'D');
+  assert(list->length == 4);
+  linked_list_reverse_mutate(list);
+  assert(list->length == 4);
+  assert((list->head->data) == (void *)'D');
+  assert((list->head->next->data) == (void *)'C');
+  assert((list->head->next->next->data) == (void *)'B');
+  assert((list->head->next->next->next->data) == (void *)'A');
+}
--- a/test/linked_list_test.h
+++ b/test/linked_list_test.h
@ -0,0 +1,18 @@
+#ifndef __LINKED_LIST_TEST__
+#define __LINKED_LIST_TEST__
+
+void linked_list_test();
+
+void linked_list_initialization_test();
+
+void linked_list_add_in_head_test();
+
+void linked_list_delete_in_head_test();
+
+void linked_list_add_after_last_test();
+
+void linked_list_reverse_test();
+
+void linked_list_reverse_mutate_test();
+
+#endif
--- a/test/main.c
+++ b/test/main.c
@ -0,0 +1,24 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "character_test.h"
+#include "convert_test.h"
+#include "dictionary_test.h"
+#include "linked_list_test.h"
+#include "mathematics_test.h"
+#include "queue_test.h"
+#include "stack_test.h"
+#include "string_test.h"
+
+int main() {
+  character_test();
+  convert_test();
+  dictionary_test();
+  linked_list_test();
+  mathematics_test();
+  queue_test();
+  stack_test();
+  string_test();
+  printf("Success: Tests passed!\n");
+  return EXIT_SUCCESS;
+}
--- a/test/mathematics_test.c
+++ b/test/mathematics_test.c
@ -0,0 +1,62 @@
+#include "mathematics_test.h"
+
+#include <assert.h>
+
+#include "libcproject.h"
+
+void mathematics_test() {
+  mathematics_absolute_value_test();
+  mathematics_pow_test();
+  mathematics_root_test();
+  mathematics_square_root_test();
+  mathematics_factorial_test();
+}
+
+void mathematics_absolute_value_test() {
+  assert(mathematics_absolute_value(0) == 0);
+  assert(mathematics_absolute_value(-0) == 0);
+  assert(mathematics_absolute_value(1) == 1);
+  assert(mathematics_absolute_value(-1) == 1);
+  assert(mathematics_absolute_value(2) == 2);
+  assert(mathematics_absolute_value(-2) == 2);
+}
+
+void mathematics_pow_test() {
+  assert(mathematics_pow(0, 0) == 1);
+  assert(mathematics_pow(0, 1) == 0);
+  assert(mathematics_pow(2, 2) == 4);
+  assert(mathematics_pow(5, 2) == 25);
+  assert(mathematics_pow(3, 3) == 27);
+  assert(mathematics_pow(7, 5) == 16807);
+}
+
+void mathematics_root_test() {
+  assert(mathematics_get_is_equal(mathematics_root(0, 0), 0));
+  assert(mathematics_get_is_equal(mathematics_root(0, 1), 0));
+  assert(mathematics_get_is_equal(mathematics_root(2, 2), 1));
+  assert(mathematics_get_is_equal(mathematics_root(27, 3), 3));
+  assert(mathematics_get_is_equal(mathematics_root(16807, 5), 7));
+}
+
+void mathematics_square_root_test() {
+  assert(mathematics_get_is_equal(mathematics_square_root(0), 0));
+  assert(mathematics_get_is_equal(mathematics_square_root(1), 1));
+  assert(mathematics_get_is_equal(mathematics_square_root(4), 2));
+  assert(mathematics_get_is_equal(mathematics_square_root(9), 3));
+  assert(mathematics_get_is_equal(mathematics_square_root(25), 5));
+  assert(mathematics_get_is_equal(mathematics_square_root(100), 10));
+}
+
+void mathematics_factorial_test() {
+  assert(mathematics_factorial(0) == 1);
+  assert(mathematics_factorial(1) == 1);
+  assert(mathematics_factorial(2) == 2);
+  assert(mathematics_factorial(3) == 6);
+  assert(mathematics_factorial(4) == 24);
+  assert(mathematics_factorial(5) == 120);
+  assert(mathematics_factorial(6) == 720);
+  assert(mathematics_factorial(7) == 5040);
+  assert(mathematics_factorial(8) == 40320);
+  assert(mathematics_factorial(9) == 362880);
+  assert(mathematics_factorial(10) == 3628800);
+}
--- a/test/mathematics_test.h
+++ b/test/mathematics_test.h
@ -0,0 +1,16 @@
+#ifndef __MATHEMATICS_TEST__
+#define __MATHEMATICS_TEST__
+
+void mathematics_test();
+
+void mathematics_absolute_value_test();
+
+void mathematics_pow_test();
+
+void mathematics_root_test();
+
+void mathematics_square_root_test();
+
+void mathematics_factorial_test();
+
+#endif
--- a/test/queue_test.c
+++ b/test/queue_test.c
@ -0,0 +1,44 @@
+#include "queue_test.h"
+
+#include <assert.h>
+#include <stdint.h>
+#include <stdlib.h>
+
+#include "libcproject.h"
+
+void queue_test() {
+  queue_initialization_test();
+  queue_push_test();
+  queue_pop_test();
+}
+
+void queue_initialization_test() {
+  struct queue *queue = queue_initialization();
+  assert(queue->length == 0);
+  assert(queue->first == NULL);
+}
+
+void queue_push_test() {
+  struct queue *queue = queue_initialization();
+  queue_push(queue, (void *)4);
+  queue_push(queue, (void *)8);
+  queue_push(queue, (void *)15);
+  assert(queue->length == 3);
+  assert(((uintptr_t)queue->first->data) == 4);
+  assert(((uintptr_t)queue->first->next->data) == 8);
+  assert(((uintptr_t)queue->first->next->next->data) == 15);
+  assert(queue->first->next->next->next == NULL);
+}
+
+void queue_pop_test() {
+  struct queue *queue = queue_initialization();
+  queue_push(queue, (void *)4);
+  queue_push(queue, (void *)8);
+  queue_push(queue, (void *)15);
+  void *node = queue_pop(queue);
+  assert(queue->length == 2);
+  assert(((uintptr_t)node) == 4);
+  assert(((uintptr_t)queue->first->data) == 8);
+  assert(((uintptr_t)queue->first->next->data) == 15);
+  assert(queue->first->next->next == NULL);
+}
--- a/test/queue_test.h
+++ b/test/queue_test.h
@ -0,0 +1,12 @@
+#ifndef __QUEUE_TEST__
+#define __QUEUE_TEST__
+
+void queue_test();
+
+void queue_initialization_test();
+
+void queue_push_test();
+
+void queue_pop_test();
+
+#endif
--- a/test/stack_test.c
+++ b/test/stack_test.c
@ -0,0 +1,44 @@
+#include "stack_test.h"
+
+#include <assert.h>
+#include <stdint.h>
+#include <stdlib.h>
+
+#include "libcproject.h"
+
+void stack_test() {
+  stack_initialization_test();
+  stack_push_test();
+  stack_pop_test();
+}
+
+void stack_initialization_test() {
+  struct stack *stack = stack_initialization();
+  assert(stack->length == 0);
+  assert(stack->first == NULL);
+}
+
+void stack_push_test() {
+  struct stack *stack = stack_initialization();
+  stack_push(stack, (void *)4);
+  stack_push(stack, (void *)8);
+  stack_push(stack, (void *)15);
+  assert(stack->length == 3);
+  assert(((uintptr_t)stack->first->data) == 15);
+  assert(((uintptr_t)stack->first->next->data) == 8);
+  assert(((uintptr_t)stack->first->next->next->data) == 4);
+  assert(stack->first->next->next->next == NULL);
+}
+
+void stack_pop_test() {
+  struct stack *stack = stack_initialization();
+  stack_push(stack, (void *)4);
+  stack_push(stack, (void *)8);
+  stack_push(stack, (void *)15);
+  void *node = stack_pop(stack);
+  assert(stack->length == 2);
+  assert(((uintptr_t)node) == 15);
+  assert(((uintptr_t)stack->first->data) == 8);
+  assert(((uintptr_t)stack->first->next->data) == 4);
+  assert(stack->first->next->next == NULL);
+}
--- a/test/stack_test.h
+++ b/test/stack_test.h
@ -0,0 +1,12 @@
+#ifndef __STACK_TEST__
+#define __STACK_TEST__
+
+void stack_test();
+
+void stack_initialization_test();
+
+void stack_push_test();
+
+void stack_pop_test();
+
+#endif
--- a/test/string_test.c
+++ b/test/string_test.c
@ -0,0 +1,222 @@
+#include "string_test.h"
+
+#include <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "libcproject.h"
+#include "test.h"
+
+void string_test() {
+  string_get_length_test();
+  string_to_uppercase_test();
+  string_to_lowercase_test();
+  string_replace_test();
+  string_trim_start_test();
+  string_trim_end_test();
+  string_trim_test();
+  string_copy_test();
+  string_capitalize_test();
+  string_total_occurrences_of_character_test();
+  string_reverse_test();
+  string_get_is_equal_test();
+  string_get_is_integer_test();
+  string_split_test();
+  string_join_test();
+  string_concatenate_test();
+  string_get_has_unique_characters_test();
+  string_substring_test();
+  string_get_is_substring_test();
+  string_get_formatted_number_test();
+  string_get_last_occurence_of_character_test();
+  string_starts_with_test();
+  string_ends_with_test();
+}
+
+void string_get_length_test() {
+  char *string = "Hello World!";
+  size_t string_length = string_get_length(string);
+  assert(string_length == 12);
+}
+
+void string_to_uppercase_test() {
+  char *string = "heLlO world";
+  string = string_to_uppercase(string);
+  assert(assert_string_equal(string, "HELLO WORLD"));
+}
+
+void string_to_lowercase_test() {
+  char *string = "HellO WoRLd";
+  string = string_to_lowercase(string);
+  assert(assert_string_equal(string, "hello world"));
+}
+
+void string_replace_test() {
+  char *string = "hello world";
+  string = string_replace(string, 'l', 'z');
+  assert(assert_string_equal(string, "hezzo worzd"));
+}
+
+void string_trim_start_test() {
+  char *string = "      hello world      ";
+  string = string_trim_start(string);
+  assert(assert_string_equal(string, "hello world      "));
+}
+
+void string_trim_end_test() {
+  char *string = "      hello world      ";
+  string = string_trim_end(string);
+  assert(assert_string_equal(string, "      hello world"));
+}
+
+void string_trim_test() {
+  char *string = "      hello world      ";
+  string = string_trim(string);
+  assert(assert_string_equal(string, "hello world"));
+}
+
+void string_copy_test() {
+  char *string = "hello world";
+  char *string2 = string_copy(string);
+  assert(assert_string_equal(string, string2));
+  string2[0] = 'a';
+  assert(assert_string_not_equal(string, string2));
+  assert(assert_string_equal(string, "hello world"));
+  assert(assert_string_equal(string2, "aello world"));
+}
+
+void string_capitalize_test() {
+  char *string = "hello world";
+  string = string_capitalize(string);
+  assert(assert_string_equal(string, "Hello world"));
+}
+
+void string_total_occurrences_of_character_test() {
+  char *string = "hello world";
+  assert(string_total_occurrences_of_character(string, 'l') == 3);
+}
+
+void string_reverse_test() {
+  char *string = "hello world";
+  string = string_reverse(string);
+  assert(assert_string_equal(string, "dlrow olleh"));
+}
+
+void string_get_is_equal_test() {
+  char *string1 = "hello world";
+  char *string2 = "dlrow olleh";
+  char *string3 = "dlrow olleh";
+  assert(!string_get_is_equal(string1, string2));
+  assert(string_get_is_equal(string1, string1));
+  assert(string_get_is_equal(string2, string3));
+}
+
+void string_get_is_integer_test() {
+  assert(string_get_is_integer("1"));
+  assert(string_get_is_integer("12"));
+  assert(string_get_is_integer("-12"));
+  assert(!string_get_is_integer("1 000"));
+  assert(!string_get_is_integer("abc"));
+  assert(!string_get_is_integer("- 12"));
+  assert(!string_get_is_integer(" -12"));
+  assert(!string_get_is_integer("-12 "));
+  assert(!string_get_is_integer("-"));
+}
+
+void string_split_test() {
+  char *string = "abc def ghij kl";
+  size_t result_length = 0;
+  char **result = string_split(string, ' ', &result_length);
+  assert(result_length == 4);
+  assert(assert_string_equal(result[0], "abc"));
+  assert(assert_string_equal(result[1], "def"));
+  assert(assert_string_equal(result[2], "ghij"));
+  assert(assert_string_equal(result[3], "kl"));
+}
+
+void string_join_test() {
+  char *string = "abc def ghij kl";
+  size_t result_length = 0;
+  char **result = string_split(string, ' ', &result_length);
+  char *new_string = string_join(result, ' ', result_length);
+  char *new_string2 = string_join(result, '+', result_length);
+  assert(assert_string_equal(new_string, string));
+  assert(assert_string_equal(new_string2, "abc+def+ghij+kl"));
+}
+
+void string_concatenate_test() {
+  assert(assert_string_equal(string_concatenate("abc", "def"), "abcdef"));
+  assert(assert_string_equal(string_concatenate("abc ", " defghi"), "abc  defghi"));
+}
+
+void string_get_has_unique_characters_test() {
+  assert(string_get_has_unique_characters("ABCDEF"));
+  assert(!string_get_has_unique_characters("AAABCDEF"));
+  assert(!string_get_has_unique_characters("AaaBCDEF"));
+}
+
+void string_substring_test() {
+  char *string = "abcdef";
+  char *substring = string_substring(string, 1, 3);
+  assert(assert_string_equal(substring, "bcd"));
+}
+
+void string_get_is_substring_test() {
+  char *string = "abcdef";
+  assert(string_get_is_substring(string, "abc"));
+  assert(string_get_is_substring(string, "bcd"));
+  assert(string_get_is_substring(string, "de"));
+  assert(string_get_is_substring(string, "f"));
+  assert(!string_get_is_substring(string, "af"));
+  assert(string_get_is_substring("3662277", "2277"));
+  assert(string_get_is_substring("3662277", "62"));
+  assert(!string_get_is_substring("3662277", "322"));
+}
+
+void string_get_formatted_number_test() {
+  assert(assert_string_equal(string_get_formatted_number(1000, " "), "1 000"));
+  assert(assert_string_equal(string_get_formatted_number(123, ","), "123"));
+  assert(assert_string_equal(string_get_formatted_number(1234, ","), "1,234"));
+  assert(assert_string_equal(string_get_formatted_number(12345, ","), "12,345"));
+  assert(assert_string_equal(string_get_formatted_number(123456, ","), "123,456"));
+  assert(assert_string_equal(string_get_formatted_number(1234567, ","), "1,234,567"));
+  assert(assert_string_equal(string_get_formatted_number(12345678, ","), "12,345,678"));
+  assert(assert_string_equal(string_get_formatted_number(123456789, ","), "123,456,789"));
+  assert(assert_string_equal(string_get_formatted_number(1234567890, ","), "1,234,567,890"));
+  assert(assert_string_equal(string_get_formatted_number(-123, ","), "-123"));
+  assert(assert_string_equal(string_get_formatted_number(-1234, ","), "-1,234"));
+  assert(assert_string_equal(string_get_formatted_number(-12345, ","), "-12,345"));
+  assert(assert_string_equal(string_get_formatted_number(-123456, ","), "-123,456"));
+  assert(assert_string_equal(string_get_formatted_number(-1234567, ","), "-1,234,567"));
+  assert(assert_string_equal(string_get_formatted_number(-12345678, ","), "-12,345,678"));
+  assert(assert_string_equal(string_get_formatted_number(-123456789, ","), "-123,456,789"));
+  assert(assert_string_equal(string_get_formatted_number(-1234567890, ","), "-1,234,567,890"));
+}
+
+void string_get_last_occurence_of_character_test() {
+  char *string = "abcdef";
+  assert(assert_string_equal(string_get_last_occurence_of_character(string, 'a'), "abcdef"));
+  assert(assert_string_equal(string_get_last_occurence_of_character(string, 'b'), "bcdef"));
+  assert(assert_string_equal(string_get_last_occurence_of_character(string, 'c'), "cdef"));
+  assert(assert_string_equal(string_get_last_occurence_of_character(string, 'd'), "def"));
+  assert(assert_string_equal(string_get_last_occurence_of_character(string, 'e'), "ef"));
+  assert(assert_string_equal(string_get_last_occurence_of_character(string, 'f'), "f"));
+}
+
+void string_starts_with_test() {
+  assert(string_starts_with("abcdef", "abc"));
+  assert(!string_starts_with("abcdef", "bcd"));
+  assert(!string_starts_with("abcdef", "def"));
+  assert(!string_starts_with("abcdef", "ef"));
+  assert(!string_starts_with("abcdef", "f"));
+  assert(!string_starts_with("abcdef", "abcdefg"));
+}
+
+void string_ends_with_test() {
+  assert(string_ends_with("abcdef", "def"));
+  assert(string_ends_with("abcdef", "ef"));
+  assert(string_ends_with("abcdef", "f"));
+  assert(!string_ends_with("abcdef", "abc"));
+  assert(!string_ends_with("abcdef", "bcd"));
+  assert(!string_ends_with("abcdef", "abcdefg"));
+}
--- a/test/string_test.h
+++ b/test/string_test.h
@ -0,0 +1,52 @@
+#ifndef __STRING_TEST__
+#define __STRING_TEST__
+
+void string_test();
+
+void string_get_length_test();
+
+void string_to_uppercase_test();
+
+void string_to_lowercase_test();
+
+void string_replace_test();
+
+void string_trim_start_test();
+
+void string_trim_end_test();
+
+void string_trim_test();
+
+void string_copy_test();
+
+void string_capitalize_test();
+
+void string_total_occurrences_of_character_test();
+
+void string_reverse_test();
+
+void string_get_is_equal_test();
+
+void string_get_is_integer_test();
+
+void string_split_test();
+
+void string_join_test();
+
+void string_concatenate_test();
+
+void string_get_has_unique_characters_test();
+
+void string_substring_test();
+
+void string_get_is_substring_test();
+
+void string_get_formatted_number_test();
+
+void string_get_last_occurence_of_character_test();
+
+void string_starts_with_test();
+
+void string_ends_with_test();
+
+#endif
--- a/test/test.c
+++ b/test/test.c
@ -0,0 +1,19 @@
+#include <stdbool.h>
+#include <stdio.h>
+#include <string.h>
+
+bool assert_string_equal(const char *actual, const char *expected) {
+  if (strcmp(expected, actual) != 0) {
+    printf("FAIL: expected = \"%s\" ; actual = \"%s\"\n", expected, actual);
+    return false;
+  }
+  return true;
+}
+
+bool assert_string_not_equal(const char *actual, const char *expected) {
+  if (strcmp(expected, actual) == 0) {
+    printf("FAIL: expected = \"%s\" ; actual = \"%s\"\n", expected, actual);
+    return false;
+  }
+  return true;
+}
--- a/test/test.h
+++ b/test/test.h
@ -0,0 +1,10 @@
+#ifndef __TEST__
+#define __TEST__
+
+#include <stdbool.h>
+
+bool assert_string_equal(const char *actual, const char *expected);
+
+bool assert_string_not_equal(const char *actual, const char *expected);
+
+#endif