#include<iostream>
using namespace std;
struct number
{
    long long n;
    char c='e';
} a[100005];
int top;
number want()
{
    number tmp;
    scanf("%lld%c",&tmp.n,&tmp.c);
    tmp.n%=10000;
    if(tmp.c>='0'&&tmp.c<='9')
        throw 1;
    else if(tmp.c!='+'&&tmp.c!='*')
        tmp.c='e';
    return tmp;
}
int main()
{
    top=0;
    a[++top]=want();
    while(a[1].c!='e'/*end*/)
    {
        if(a[top].c=='+')
        {
            a[++top]=want();
            continue;
        }
        if(a[top].c=='*')
        {
            number tmp=want();
            a[top].n*=tmp.n;
            a[top].n%=10000;
            a[top].c=tmp.c;
            continue;
        }
        if(a[top].c=='e')
        {
            top--;
            a[top].n+=a[top+1].n;
            a[top].n%=10000;
            a[top].c='e';
            continue;
        }
        cout<<'A';
        return 0;
    }
    cout<<a[1].n;
    return 0;
}

一开始我want写的是

if(tmp.c==EOF)
	tmp.c='e';

难道输入的末尾不是EOF吗？