QEGDzQ - Online C Compiler & Debugging Tool

#include<stdio.h>
#define SIZE 10
double stack[SIZE];
int sp;
int code;
double a,b;
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("answer:%lf\n",stack[sp-1]);
}
void reset(void)
{
sp = 0;
}
int main(void)
{
reset();
while(1) {
	 	scanf("%d",&code);
	 	switch (code)
	 	{
	 		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",&a);
	 		push(a);
	 		printf("data:%lf",a);
	 		break ;

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