p5PlqY - Online C Compiler & Debugging Tool

#include <stdio.h>

#define SIZE 10
double stack[SIZE];
int sp;

void push(double value);
double pop(void);
int isFull(void);
int isEmpty(void);
void answer(void);
void reset(void);

int main(void){
    reset();

    while(1) {
        int choice;
        double value;
        double a, b;

        scanf("%d", &choice);

        switch(choice) {
        case 1:
            b = pop();
            a = pop();
            push(a + b);
            break;

        case 2:
            b = pop();
            a = pop();
            push(a - b);
            break;

        case 3:
            b = pop();
            a = pop();
            push(a * b);
            break;

        case 4:
            b = pop();
            a = pop();
            push(a / b);
            break;

        case 5:
            scanf("%lf", &value);
            printf("data:%f\n", value);
            push(value);
            break;

        case 9:
            answer();
            return 0;
        }
    }

    return 0;
}

void push(double value)
{
    stack[sp] = value;
    sp++;
}

double pop(void)
{
    sp--;
    return stack[sp];
}

int isFull(void)
{
    return sp >= SIZE;
}

int isEmpty(void)
{
    return sp <= 0;
}

void answer(void)
{
    printf("\nanswer:%f\n", pop());
}

void reset(void)
{
    sp = 0;
}