全RE求调

#include<iostream>
#include<cstdio>
#include<cmath>
#include<cstring>
#include<string>
#include<vector>
#include<algorithm>
#include<ctime>
#include<cstdlib>
#include<stack>
using namespace std;
string s;
stack<int>z;
int a[55],n;
int main(){
    cin>>s;
    int len=s.size();
    string ss;
    for(int i=0;i<len;i++){ 
        if(a[i]=='@') break;
        if(a[i]>='0'&&a[i]<='9'){
            n=n*10+a[i]-'0';
        }
        else if(a[i]=='.'){
            z.push(n);
            n=0;
        }
        else{
            int x,y,t;
            x=z.top();
            z.pop();
            y=z.top();
            z.pop();
            if(a[i]=='+') t=x+y;
            else if(a[i]=='-') t=y-x;
            else if(a[i]=='*') t=x*y;
            else if(a[i]=='/') t=y/x;
            z.push(t);
        }   
    }
    printf("%d",z.top());
    return 0;
}