求指教 全RE..绝望的我...

#include<cstdio>
#include<stack>
using namespace std;
stack<int> expp;
char inpt;
int temp;
int x1, y1;
int main(){
    //freopen("i.txt","r",stdin);
    while(inpt = getchar() != '@'){
        if(inpt >= '0' && inpt <= '9'){
            temp = temp * 10 + (inpt-'0');
            continue;
        }else if(inpt == '.'){
            expp.push(temp);
            temp = 0;
            continue;
        }else {                                                 // 3.5.2.-*7.+@
            x1 = expp.top(); expp.pop();
            y1 = expp.top(); expp.pop();
            switch(inpt){
                case '+':
                    expp.push(y1 + x1);
                    break;
                case '-':
                    expp.push(y1 - x1);
                    break;
                case '*':
                    expp.push(y1 * x1);
                    break;
                case '/':
                    expp.push(y1 / x1);
                    break;
            }
        }
    }
    int ans = expp.top();
    printf("%d", ans);
    return 0;
}