diff --git a/challenges/camel-case/solutions/c/function/README.md b/challenges/camel-case/solutions/c/function/README.md
new file mode 100644
index 0000000..4d624ac
--- /dev/null
+++ b/challenges/camel-case/solutions/c/function/README.md
@@ -0,0 +1,3 @@
+# camel-case/c/function
+
+Created by [@Divlo](https://github.com/Divlo) on 29 September 2021.
diff --git a/challenges/camel-case/solutions/c/function/character.c b/challenges/camel-case/solutions/c/function/character.c
new file mode 100644
index 0000000..b285fc7
--- /dev/null
+++ b/challenges/camel-case/solutions/c/function/character.c
@@ -0,0 +1,20 @@
+#include "character.h"
+
+#include <stdlib.h>
+#include <string.h>
+
+void character_append(char* string, char character) {
+  size_t length = strlen(string);
+  string[length] = character;
+  string[length + 1] = '\0';
+}
+
+const char character_to_upper(const char character) {
+  char ascii_a = 'a';
+  char ascii_A = 'A';
+  char ascii_z = 'z';
+  if (character >= ascii_a && character <= ascii_z) {
+    return character + (ascii_A - ascii_a);
+  }
+  return character;
+}
diff --git a/challenges/camel-case/solutions/c/function/character.h b/challenges/camel-case/solutions/c/function/character.h
new file mode 100644
index 0000000..62699a7
--- /dev/null
+++ b/challenges/camel-case/solutions/c/function/character.h
@@ -0,0 +1,21 @@
+#ifndef CHARACTER_H
+#define CHARACTER_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 Converts the character to uppercase.
+ *
+ * @param character
+ * @return const char
+ */
+const char character_to_upper(const char character);
+
+#endif
diff --git a/challenges/camel-case/solutions/c/function/input.c b/challenges/camel-case/solutions/c/function/input.c
new file mode 100644
index 0000000..c07bb6d
--- /dev/null
+++ b/challenges/camel-case/solutions/c/function/input.c
@@ -0,0 +1,19 @@
+#include "input.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "character.h"
+
+char* input() {
+  char character;
+  size_t length = 1;
+  char* string = malloc(length * sizeof(char));
+  *string = '\0';
+  while ((character = getchar()) != '\n' && character != EOF) {
+    length++;
+    string = realloc(string, length * sizeof(char));
+    character_append(string, character);
+  }
+  return string;
+}
diff --git a/challenges/camel-case/solutions/c/function/input.h b/challenges/camel-case/solutions/c/function/input.h
new file mode 100644
index 0000000..9cd0a22
--- /dev/null
+++ b/challenges/camel-case/solutions/c/function/input.h
@@ -0,0 +1,11 @@
+#ifndef INPUT_H
+#define INPUT_H
+
+/**
+ * @brief Read a line from stdin.
+ *
+ * @return char*
+ */
+char* input();
+
+#endif
diff --git a/challenges/camel-case/solutions/c/function/solution.c b/challenges/camel-case/solutions/c/function/solution.c
new file mode 100644
index 0000000..be9aab3
--- /dev/null
+++ b/challenges/camel-case/solutions/c/function/solution.c
@@ -0,0 +1,15 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "character.h"
+#include "input.h"
+#include "string.h"
+
+int main() {
+  char* string = input();
+  string = string_trim(string);
+  string = string_camelCase(string);
+  printf("%s\n", string);
+  free(string);
+  return EXIT_SUCCESS;
+}
diff --git a/challenges/camel-case/solutions/c/function/string.c b/challenges/camel-case/solutions/c/function/string.c
new file mode 100644
index 0000000..58cb61e
--- /dev/null
+++ b/challenges/camel-case/solutions/c/function/string.c
@@ -0,0 +1,66 @@
+#include "string.h"
+
+#include <stdbool.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "character.h"
+
+char* string_trim_start(char* string) {
+  size_t string_length = strlen(string);
+  char* result = malloc(sizeof(char) * (string_length + 1));
+  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 = strlen(string);
+  char* result = malloc(sizeof(char) * (string_length + 1));
+  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_capitalize(char* string) {
+  size_t string_length = strlen(string);
+  if (string_length > 0) {
+    string[0] = character_to_upper(string[0]);
+  }
+  return string;
+}
+
+char* string_camelCase(char* string) {
+  size_t string_length = strlen(string);
+  char* result = malloc(sizeof(char) * (string_length + 1));
+  int words = 0;
+  char* current = malloc(sizeof(char) * (string_length + 1));
+  for (size_t index = 0; index < string_length; index++) {
+    if (string[index] == ' ') {
+      strcat(result, words == 0 ? current : string_capitalize(current));
+      memset(current, 0, sizeof(char) * (string_length + 1));
+      words++;
+    } else {
+      character_append(current, string[index]);
+    }
+  }
+  strcat(result, words == 0 ? current : string_capitalize(current));
+  free(current);
+  return result;
+}
diff --git a/challenges/camel-case/solutions/c/function/string.h b/challenges/camel-case/solutions/c/function/string.h
new file mode 100644
index 0000000..4680c5c
--- /dev/null
+++ b/challenges/camel-case/solutions/c/function/string.h
@@ -0,0 +1,44 @@
+#ifndef STRING_H
+#define STRING_H
+
+/**
+ * @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 Converts a string to camel case.
+ *
+ * @param string
+ * @return char*
+ */
+char* string_camelCase(char* string);
+
+/**
+ * @brief Capitalizes the string.
+ *
+ * @param string
+ * @return char*
+ */
+char* string_capitalize(char* string);
+
+#endif
diff --git a/challenges/is-palindrome/solutions/c/function/character.c b/challenges/is-palindrome/solutions/c/function/character.c
index d993469..b285fc7 100644
--- a/challenges/is-palindrome/solutions/c/function/character.c
+++ b/challenges/is-palindrome/solutions/c/function/character.c
@@ -10,10 +10,11 @@ void character_append(char* string, char character) {
 }
 
 const char character_to_upper(const char character) {
-  int a_ascii_code = (int)'a';
-  int z_ascii_code = (int)'z';
-  if (character >= a_ascii_code && character <= z_ascii_code) {
-    return character - 32;
+  char ascii_a = 'a';
+  char ascii_A = 'A';
+  char ascii_z = 'z';
+  if (character >= ascii_a && character <= ascii_z) {
+    return character + (ascii_A - ascii_a);
   }
   return character;
 }
diff --git a/challenges/is-palindrome/solutions/c/function/input.c b/challenges/is-palindrome/solutions/c/function/input.c
index cff07a3..dd5a28c 100644
--- a/challenges/is-palindrome/solutions/c/function/input.c
+++ b/challenges/is-palindrome/solutions/c/function/input.c
@@ -2,6 +2,8 @@
 
 #include <stdio.h>
 
+#include "character.h"
+
 char* input() {
   char character;
   size_t length = 1;