usaa24/cv3/program.c

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

#define STACK_SIZE 10

double stack[STACK_SIZE];
int top = 0;

void print_stack() {
    for (int i = 0; i < top; i++) {
        printf("%.2f ", stack[i]);
    }
    printf("\n");
}

int push(double value) {
    if (top >= STACK_SIZE) {
        printf("full stack\n");
        return 0;
    }
    stack[top++] = value;
    print_stack();
    return 1;
}

int pop(double *value) {
    if (top <= 0) {
        printf("not enough operands\n");
        return 0;
    }
    *value = stack[--top];
    return 1;
}

int apply_operation(char op) {
    double a, b;

    if (!pop(&b) || !pop(&a)) {
        return 0;
    }

    double result;
    switch (op) {
        case '+': result = a + b; break;
        case '-': result = a - b; break;
        case '*': result = a * b; break;
        case '/':
            if (b == 0) {
                printf("division by zero\n");
                return 0;
            }
            result = a / b;
            break;
        default:
            printf("bad input\n");
            return 0;
    }

    return push(result);
}

int main() {
    char input[100];

    while (scanf("%s", input) == 1) {
        char *end;
        double value = strtod(input, &end);

        if (*end == '\0') {
            if (!push(value)) return 0;
        } else if (input[1] == '\0' && strchr("+-*/", input[0])) {
            if (!apply_operation(input[0])) return 0;
        } else {
            printf("bad input\n");
            return 0;
        }
    }

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