105 lines
2.4 KiB
C
105 lines
2.4 KiB
C
#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <assert.h>
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#include <ctype.h>
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#define STACK_SIZE 10
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#define LINESIZE 100
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struct stack {
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float values[STACK_SIZE];
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int size;
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};
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//zakladne funkcie
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void push_stack(struct stack *s, float value) {
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if (s->size >= STACK_SIZE) {
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printf("Chyba: zasobnik je plny.\n");
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exit(1);
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}
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s->values[s->size] = value;
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s->size++;
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}
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float pop_stack(struct stack *s) {
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if (s->size <= 0) {
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printf("Chyba: zasobnik je prazdny.\n");
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exit(1);
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}
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s->size--;
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return s->values[s->size];
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}
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void print_stack(struct stack *s) {
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for (int i = 0; i < s->size; i++) {
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if (i > 0) printf(" ");
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printf("%g", s->values[i]);
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}
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printf("\n");
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}
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//pomocne funkcie
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//je retazec cislo
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int is_number(const char *str) {
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char *endptr;
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strtof(str, &endptr);
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// ak endptr ukazuje na koniec retazca, bolo to cele cislo
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return (*str != '\0' && *endptr == '\0');
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}
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int main(void) {
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struct stack s;
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memset(&s, 0, sizeof(struct stack));
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char line[LINESIZE];
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while (fgets(line, sizeof(line), stdin)) {
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line[strcspn(line, "\n")] = '\0';
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//preskocit prazdny riadok
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if (strlen(line) == 0)
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continue;
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if (is_number(line)) {
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float value = strtof(line, NULL);
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push_stack(&s, value);
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} else if (strlen(line) == 1 && strchr("+-*/", line[0])) {
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//operacia
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if (s.size < 2) {
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printf("Chyba: nedostatok operandov.\n");
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return 1;
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}
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float b = pop_stack(&s);
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float a = pop_stack(&s);
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float result;
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switch (line[0]) {
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case '+': result = a + b; break;
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case '-': result = a - b; break;
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case '*': result = a * b; break;
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case '/':
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if (b == 0) {
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printf("Chyba: delenie nulou.\n");
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return 1;
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}
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result = a / b; break;
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default:
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printf("Chyba: neznama operacia.\n");
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return 1;
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}
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push_stack(&s, result);
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} else {
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printf("Chyba: neplatny vstup.\n");
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return 1;
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}
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print_stack(&s);
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}
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return 0;
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}
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