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feat(solutions): add reverse-polish-notation/c/function
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@ -6,7 +6,7 @@ Created by [@Divlo](https://github.com/Divlo) on 29 September 2020.
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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).
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For example expression 5 1 2 + 4 / + 3 - (which is equivalent to 5 + ((1 + 2) / 4) - 3 in normal notation) should evaluate to 14.
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For example expression 5 3 + (which is equivalent to 5 + 3 in normal notation) should evaluate to 8.
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For your convenience, the input is formatted such that a space is provided between every token.
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@ -16,6 +16,8 @@ Valid operations are +, -, \*, /.
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You may assume that there won't be exceptional situations (like stack underflow or division by zero).
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All the numbers are integers; you don't need to worry about floating point numbers.
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## Source
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- [Reverse polish notation - Codewars](https://www.codewars.com/kata/52f78966747862fc9a0009ae)
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@ -0,0 +1,3 @@
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# reverse-polish-notation/c/function
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Created by [@Divlo](https://github.com/Divlo) on 12 October 2021.
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@ -0,0 +1,10 @@
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#include "character.h"
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#include <stdlib.h>
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#include <string.h>
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void character_append(char* string, char character) {
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size_t length = strlen(string);
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string[length] = character;
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string[length + 1] = '\0';
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}
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@ -0,0 +1,13 @@
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#ifndef __CHARACTER__
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#define __CHARACTER__
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/**
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* @brief Append a character to a string, assuming string points to an array
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* with enough space.
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*
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* @param string
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* @param character
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*/
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void character_append(char* string, char character);
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#endif
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@ -0,0 +1,19 @@
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#include "input.h"
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#include <stdio.h>
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#include <stdlib.h>
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#include "character.h"
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char* input() {
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char character;
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size_t length = 1;
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char* string = malloc(length * sizeof(char));
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*string = '\0';
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while ((character = getchar()) != '\n' && character != EOF) {
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length++;
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string = realloc(string, length * sizeof(char));
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character_append(string, character);
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}
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return string;
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}
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@ -0,0 +1,11 @@
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#ifndef __INPUT__
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#define __INPUT__
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/**
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* @brief Read a line from stdin.
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*
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* @return char*
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*/
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char* input();
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#endif
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@ -0,0 +1,49 @@
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#include <ctype.h>
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#include <stdbool.h>
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#include <stdint.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include "input.h"
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#include "stack.h"
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bool is_integer(char* string) {
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size_t string_length = strlen(string);
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for (size_t index = 0; index < string_length; index++) {
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if (!isdigit(string[index])) {
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return false;
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}
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}
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return true;
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}
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int main() {
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char* string = input();
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struct Stack* stack = stack_initialization();
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char* token = strtok(string, " ");
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while (token != NULL) {
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if (is_integer(token)) {
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intptr_t number;
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sscanf(token, "%ld", &number);
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stack_push(stack, (void*)number);
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} else {
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intptr_t number1 = (intptr_t)stack_pop(stack);
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intptr_t number2 = (intptr_t)stack_pop(stack);
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intptr_t result = 0;
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if (strcmp(token, "+") == 0) {
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result = number2 + number1;
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} else if (strcmp(token, "-") == 0) {
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result = number2 - number1;
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} else if (strcmp(token, "*") == 0) {
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result = number2 * number1;
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} else {
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result = number2 / number1;
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}
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stack_push(stack, (void*)result);
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}
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token = strtok(NULL, " ");
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}
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printf("%ld\n", (intptr_t)stack_pop(stack));
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return EXIT_SUCCESS;
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}
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#include "stack.h"
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#include <stdio.h>
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#include <stdlib.h>
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struct Stack *stack_initialization() {
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struct Stack *stack = malloc(sizeof(*stack));
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if (stack == NULL) {
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exit(EXIT_FAILURE);
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}
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stack->first = NULL;
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stack->length = 0;
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return stack;
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}
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void stack_push(struct Stack *stack, void *data) {
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struct Node *node_new = malloc(sizeof(*node_new));
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if (stack == NULL || data == NULL) {
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exit(EXIT_FAILURE);
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}
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node_new->data = data;
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node_new->next = stack->first;
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stack->first = node_new;
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stack->length = stack->length + 1;
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}
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void *stack_pop(struct Stack *stack) {
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if (stack == NULL) {
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exit(EXIT_FAILURE);
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}
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struct Node *node = stack->first;
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void *data = NULL;
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if (node != NULL) {
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stack->first = node->next;
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data = node->data;
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free(node);
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}
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stack->length = stack->length - 1;
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return data;
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}
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#ifndef __STACK__
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#define __STACK__
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#include <stdlib.h>
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// LIFO = Last In First Out
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struct Stack {
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struct Node *first;
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size_t length;
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};
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struct Node {
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void *data;
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struct Node *next;
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};
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struct Stack *stack_initialization();
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void stack_push(struct Stack *stack, void *data);
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void *stack_pop(struct Stack *stack);
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#endif
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@ -1 +1 @@
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3.5
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1 3 +
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3.5
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4
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1 3 +
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5 3 *
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4
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15
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1 3 *
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1 3 -
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3
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-2
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1 3 -
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10 2 /
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-2
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5
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4 2 /
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5 3 + 12 8 + * 10 /
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2
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16
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5 3 + 12 8 + * 10 /
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16
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