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feat(solutions): add reverse-polish-notation/c/function

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Divlo 2021-10-12 22:48:23 +02:00
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commit cc8bb07a96
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21 changed files with 181 additions and 13 deletions

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@ -6,7 +6,7 @@ Created by [@Divlo](https://github.com/Divlo) on 29 September 2020.
Your job is to create a calculator which evaluates expressions in Reverse Polish notation (a mathematical notation in which operators follow their operands. It does not need any parentheses as long as each operator has a fixed number of operands).
For example expression 5 1 2 + 4 / + 3 - (which is equivalent to 5 + ((1 + 2) / 4) - 3 in normal notation) should evaluate to 14.
For example expression 5 3 + (which is equivalent to 5 + 3 in normal notation) should evaluate to 8.
For your convenience, the input is formatted such that a space is provided between every token.
@ -16,6 +16,8 @@ Valid operations are +, -, \*, /.
You may assume that there won't be exceptional situations (like stack underflow or division by zero).
All the numbers are integers; you don't need to worry about floating point numbers.
## Source
- [Reverse polish notation - Codewars](https://www.codewars.com/kata/52f78966747862fc9a0009ae)

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@ -0,0 +1,3 @@
# reverse-polish-notation/c/function
Created by [@Divlo](https://github.com/Divlo) on 12 October 2021.

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@ -0,0 +1,10 @@
#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';
}

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@ -0,0 +1,13 @@
#ifndef __CHARACTER__
#define __CHARACTER__
/**
* @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);
#endif

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@ -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;
}

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@ -0,0 +1,11 @@
#ifndef __INPUT__
#define __INPUT__
/**
* @brief Read a line from stdin.
*
* @return char*
*/
char* input();
#endif

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@ -0,0 +1,49 @@
#include <ctype.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "input.h"
#include "stack.h"
bool is_integer(char* string) {
size_t string_length = strlen(string);
for (size_t index = 0; index < string_length; index++) {
if (!isdigit(string[index])) {
return false;
}
}
return true;
}
int main() {
char* string = input();
struct Stack* stack = stack_initialization();
char* token = strtok(string, " ");
while (token != NULL) {
if (is_integer(token)) {
intptr_t number;
sscanf(token, "%ld", &number);
stack_push(stack, (void*)number);
} else {
intptr_t number1 = (intptr_t)stack_pop(stack);
intptr_t number2 = (intptr_t)stack_pop(stack);
intptr_t result = 0;
if (strcmp(token, "+") == 0) {
result = number2 + number1;
} else if (strcmp(token, "-") == 0) {
result = number2 - number1;
} else if (strcmp(token, "*") == 0) {
result = number2 * number1;
} else {
result = number2 / number1;
}
stack_push(stack, (void*)result);
}
token = strtok(NULL, " ");
}
printf("%ld\n", (intptr_t)stack_pop(stack));
return EXIT_SUCCESS;
}

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@ -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 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 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;
}

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@ -0,0 +1,23 @@
#ifndef __STACK__
#define __STACK__
#include <stdlib.h>
// LIFO = Last In First Out
struct Stack {
struct Node *first;
size_t length;
};
struct Node {
void *data;
struct Node *next;
};
struct Stack *stack_initialization();
void stack_push(struct Stack *stack, void *data);
void *stack_pop(struct Stack *stack);
#endif

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@ -1 +1 @@
3.5
1 3 +

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@ -1 +1 @@
1 3 +
5 3 *

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@ -1 +1 @@
1 3 *
1 3 -

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@ -1 +1 @@
1 3 -
10 2 /

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@ -1 +1 @@
4 2 /
5 3 + 12 8 + * 10 /

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@ -1 +0,0 @@
5 3 + 12 8 + * 10 /