奇技淫巧++

#include<bits/stdc++.h>
using namespace std;
int a,p,q,r;
char t;
stack <int> st;
int main()
{
    while(1)
    {
        cin>>t;
        if(t=='@') break;else cin.putback(t);
        cin>>a;
        st.push(a);
        cin>>t;
        if(t=='@') break;
        if(t=='.') cin>>t;
        while ((t<='0'||t>='9')&&t!='@')
        {
        q=st.top();st.pop();
        p=st.top();st.pop();
        switch(t)
        {
            case'+':r=p+q;break;
            case'-':r=p-q;break;
            case'*':r=p*q;break;
            case'/':r=p/q;break;
        }
        st.push(r);
        cin>>t;
        }
        cin.putback(t);
    }
    cout<<st.top();
    return 0;
}