关于c++字符串操作与动态空间管理的编程问题

#include <iostream>
#include <vector>
#include <string>
#include <limits>
#include <algorithm>
using namespace std;

int main( void )
{
    char a;
    vector<string> s;

    cin >> a;
    cin.ignore( numeric_limits<streamsize>::max(), '\n' );
    for( string line; getline(cin,line) && line!="@"; )
    {
        line.erase( remove(line.begin(),line.end(),a), line.end() );
        s.push_back( line );
    }

    sort( s.begin(), s.end(), greater<string>() );
    copy( s.begin(), s.end(), std::ostream_iterator<string>(cout,"\n") );
}