include iostream include fstream include vector include list include a

#include <iostream>
#include <fstream>
#include <vector>
#include <list>
#include <algorithm>

using namespace std;

int main() {
    ifstream in("input.txt");
    if (in) {
        list<int> v;
        int x;
        while (in >> x) v.push_back(x);
        cout << "Введите искомое число:";
        cin >> x;
        int how_much = count(v.begin(), v.end(), x);
        cout << how_much << endl;
        list<int> pos_list;

        for (list<int>::iterator pos = v.begin(); pos != v.end(); ++pos) {
            if(*pos == how_much){
                pos_list.push_back(pos);
            }
        }

        list<int>::iterator i;
        for (i = pos_list.begin(); i != pos_list.end(); ++i)
            cout << *i << " ";
        return 0;
    }
    return 1;
}