usaa24/cv3/program.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>

#define STACK_SIZE 10

struct stack {
    float values[STACK_SIZE];
    int size;
};

void print_stack(struct stack* s) {
    for (int i = 0; i < s->size; i++) {
        printf("%.2f", s->values[i]);
        if (i < s->size - 1) {
            printf(" ");
        } else {
            printf(" ");
        }
    }
    printf("\n");
}

void push_stack(struct stack* s, float value) {
    if (s->size >= STACK_SIZE) {
        printf("full stack\n");
        exit(0);
    }
    s->values[s->size++] = value;
}

float pop_stack(struct stack* s) {
    if (s->size == 0) {
        printf("empty stack\n");
        exit(0);
    }
    return s->values[--s->size];
}

int is_operator(char* input) {
    return (strcmp(input, "+") == 0 || strcmp(input, "-") == 0 ||
            strcmp(input, "*") == 0 || strcmp(input, "/") == 0);
}

int is_valid_float(char* input) {
    char* endptr;
    strtod(input, &endptr);
    return *endptr == '\0';
}

void perform_operation(struct stack* s, char* operator) {
    if (s->size < 2) {
        printf("not enough operands\n");
        exit(0);
    }

    float b = pop_stack(s);
    float a = pop_stack(s);
    float result;

    if (strcmp(operator, "+") == 0) {
        result = a + b;
    } else if (strcmp(operator, "-") == 0) {
        result = a - b;
    } else if (strcmp(operator, "*") == 0) {
        result = a * b;
    } else if (strcmp(operator, "/") == 0) {
        if (b == 0) {
            printf("division by zero\n");
            exit(0);
        }
        result = a / b;
    } else {
        printf("Chyba: neplatna operacia\n");
        exit(0);
    }

    push_stack(s, result);
}

int main() {
    char input[100];
    struct stack mystack;
    mystack.size = 0;

    while (fgets(input, sizeof(input), stdin) != NULL) {
        input[strlen(input) - 1] = '\0';

        if (is_valid_float(input)) {
            float value = atof(input);
            push_stack(&mystack, value);
        } else if (is_operator(input)) {
            perform_operation(&mystack, input);
        } else {
            printf("bad input\n");
            return 0;
        }

        print_stack(&mystack);
    }

    printf("no input\n");
    return 0;
}