c++stl80分求助

#include<bits/stdc++.h>
using namespace std;

stack<char>v;
int main()
{
    char c;
    while(cin>>c)
    {if(c=='-')
    {cout<<"-";}
    else
        {v.push(c);}
    }
    if(v.top()=='0')
    {v.pop();}
    while(!v.empty())
    {cout<<v.top();
    v.pop();
    }

    return 0;
}