ACM题目————STL练习之字符串替换

//Asimple
#include <iostream>
#include <string>

using namespace std;
string str, s1="you", s2="we";

int main()
{
    int pos;
    while( getline(cin,str) )
    {
        pos = str.find(s1,0);
        while( pos != string::npos )
        {
            str.replace(pos,3,s2);
            pos = str.find(s1,pos+1);
        }
        cout << str << endl ;
    }
    return 0;
}