84 lines
2.3 KiB
C
84 lines
2.3 KiB
C
#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#define STACK_SIZE 10
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typedef struct {
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float values[STACK_SIZE];
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int size;
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} stack;
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void stack_print (stack* stack);
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void stack_push (stack* stack,float value);
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float stack_pop (stack* stack);
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void my_exit(int flag, const char* input);
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int main(void) {
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stack* p_stack = (stack*) malloc(sizeof(stack));
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memset(p_stack, 0, sizeof(stack));
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while(1) {
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char str[128] = { 0 };
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char* tres = fgets(str, 128, stdin);
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if(tres == NULL || str[0] == 0 || (str[1] == 0 && str[0] == '\n'))
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my_exit(1, "no_input");
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str[strlen(str) - 1] = 0;
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// if number
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if(strlen(str) > 1 || (str[0] >= '0' && str[0] <= '9')) {
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char *p;
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errno = 0;
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float res = strtod(str,&p);
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my_exit(str[0] == '.' || errno || (*p) != 0, "bad input");
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stack_push(p_stack, res);
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}
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else {
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my_exit(p_stack->size < 2, "not enough operands");
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float b = stack_pop(p_stack);
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float a = stack_pop(p_stack);
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char op = str[0];
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float res;
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switch (op) {
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case '+':
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res = a + b;
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break;
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case '-':
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res = a - b;
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break;
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case '*':
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res = a * b;
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break;
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case '/':
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my_exit(b == 0.f, "division by zero");
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res = a / b;
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break;
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default:
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my_exit(1, "bad input");
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}
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stack_push(p_stack, res);
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}
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stack_print(p_stack);
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}
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free(p_stack);
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}
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void stack_print(stack* st) {
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for(int i = 0; i < st->size; i++)
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printf("%.2f ",st->values[i]);
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printf("\n");
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}
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void stack_push(stack* st, float push_value) {
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if(st->size < STACK_SIZE)
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st->values[st->size++] = push_value;
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}
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float stack_pop(stack* st) {
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if(st->size > 0)
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return st->values[--st->size];
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}
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void my_exit(int flag, const char* input) {
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if (flag) {
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printf("%s\n", input);
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exit(0);
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}
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} |