poj 1318 Word Amalgamation

#include <iostream>
#include <string>
#include <set>
using namespace std;
bool match(string str1,string str2)
{
    for(int i=0;i<str1.size();++i)
    {
        if(str2.find_first_of(str1[i])==string::npos)
            return false;
        else
            str2.erase(str2.find_first_of(str1[i]),1);
    }
    return true;
}
int main()
{
    string str,test;
    bool tag;
    set<string> dictionary;
    set<string>::iterator pos;
    while(cin>>str&&str!="XXXXXX")
    {
        dictionary.insert(str);
    }
    while(cin>>test&&test!="XXXXXX")
    {
        tag=0;
        for(pos=dictionary.begin();pos!=dictionary.end();++pos)
        {
            if((*pos).size()!=test.size())
                continue;
            if(match(*pos,test))
                tag=1,cout<<*pos<<endl;
        }
        if(!tag)
            printf("NOT A VALID WORD\n");
        printf("******\n");
    }
    return 0;
}