Set #1(12)

#include <fstream>
#include <algorithm>
#include <set>
#include <vector>
using namespace std;

ifstream fin("input.txt");
ofstream fout("output.txt");

int main()
{
        int size, tmp;
        fin >> size;

        set<int> set1;
        set<int> set2;
        int i=1;
        while(fin >> tmp)
        {
            if (tmp<0) tmp*=-1;
            while (tmp>0)
            {
                int some=tmp%10;
                if (set1.count(some)==0)
                {
                    set1.insert(some);
                    set2.erase(some);
                }
                else
                {
                    set1.erase(some);
                    set2.insert(some);
                }
                tmp=tmp/10;

            }


            fout << "Number" << i << ":";
            for(set<int>::iterator it=set2.begin();it!=set2.end();it++)
                fout << *it << " ";
            fout << endl;
            i++;

            set1.clear();
            set2.clear();
        }
        return 0;
}