практика_сеты1_2

#include <set>
#include <fstream>
#include <iterator>
#include <algorithm>
#include <vector>

using namespace std;

int main()
{
    set <int> s;
    set <int> s2;
    for (int i = 0; i < 10; i++)
        s2.insert(i);
    vector <int> result;
    ifstream in("input.txt");
    int tmp;
    while (in >> tmp)
    {
        tmp = abs(tmp);
        while (tmp)
        {
            s.insert(tmp % 10);
            tmp /= 10;
        }
    }
    in.close();
    ofstream out("output.txt");
    set_difference(s2.begin(), s2.end(), s.begin(), s.end(), back_inserter(result));
    for (vector<int>::iterator iter = result.begin(); iter != result.end(); iter++)
        out << *iter << " ";
    if (result.empty()) out << "There are no different number";
    out.close();
    return 0;
}