P1449后缀表达式，一输入就蹦

#include<bits/stdc++.h>
using namespace std;
char s;
int a[55]; 
int top;
int x,y,z;
void fufu(int fu)
{
	x=a[fu];
	a[fu]=0;
	fu--;
	y=a[fu];
	a[fu]=0;
	fu--;
	top=fu+1;
}
int main()
{
	ios::sync_with_stdio(false);
	cin.tie(0);
	cout.tie(0);
	for(;;)
	{
		cin>>s;
		if(s=='@')break;
		if(s>=48 && s<=57)a[top]=(int)s-48,top++;
		if(s=='-')
		{
			fufu(top-1);
			z=y-x;
			a[top]=z;
			cout<<"fufu:"<<x<<" "<<y<<" "<<a[top]<<top<<endl;
			top++;
		}
		else if(s=='+')
		{
			fufu(top-1);
			z=y+x;
			a[top]=z;cout<<"fufu:"<<x<<" "<<y<<" "<<a[top]<<top<<endl;
			top++;
		}
		else if(s=='*')
		{
			fufu(top-1);
			z=y*x;
			a[top]=z;cout<<"fufu:"<<x<<" "<<y<<" "<<a[top]<<top<<endl;
			top++;
		}
		else if(s=='/')
		{
			fufu(top-1);
			z=y/x;
			a[top]=z;cout<<"fufu:"<<x<<" "<<y<<" "<<a[top]<<top<<endl;
			top++;
		}
		
	}
	cout<<a[top-1];
	return 0;
 }