停止工作

#include<iostream>
#include<cstdio>
#include<stack>
using namespace std;
stack <int> ch;
int main(){
    int i=0;
    string s;
   getline(cin,s);
    while(s[i]!='@')
    {
        if(s[i]!='.'&&s[i]!='+'&&s[i]!='-'&&s[i]!='*'&&s[i]!='/'){        
        ch.push (s[i]);
       }
        int x=ch.top(); ch.pop();
        int y=ch.top(); ch.pop();
        switch(s[i]){
            case '+':ch.push(x+y);break;
            case '-':ch.push(y-x);break;
            case '*':ch.push(x*y);break;
            case '/':ch.push(y/x);break;

        }

    }   
    i++;
    int w=ch.top();
      cout<<w;
    return 0;
}