POJ 1572 Automatic Editing 字符串替换，replace就够了

　　题意不难理解，但是一开始还是没有看清楚题目。Replace the first occurrence of the find string within the text by the replace-by string, then try to perform the same replacement again on the new text. Continue until the find string no longer occurs within the text, and then move on to the next rule.这个地方我贡献了几次TL。它的意思是替换完第n个字符串后，继续判断是否还能被这个字符串替换，否则移至下一个。

#include <iostream>
#include <cstdio>
#include <string>
using namespace std;

int main()
{
    //freopen("in.txt","r",stdin);
    while(1)
    {
        int n;
        scanf("%d",&n);
        if(n==0)
            break;
        string str1[12];
        string str2[12];
        getchar();
        for(int i=0; i<n; i++)
        {
            getline(cin,str1[i]);
            getline(cin,str2[i]);
        }
        string str3;
        getline(cin,str3);
        for(int i=0; i<n; i++)
            while(1)
            {
                int index=str3.find(str1[i]); //查找要替换的字符串位置，没有返回string::npos
                if(index==string::npos)
                    break;
                str3=str3.replace(index,str1[i].length(),str2[i]); //replace函数直接替换，或者用erase和insert也行
                //str3.erase(index,str1[i].length());
                //str3.insert(index,str2[i]);
            }
        cout<<str3<<endl;
    }
    return 0;
}