Цикл

#include <iostream>
using namespace std;
int main () {
    int t, s, d, e, i = 0, g = 999;
    while (g != 10000) {
        g++;
        t = g / 1000;
        s = g / 100 % 10;
        d = g / 10 % 10;
        e = g % 10;
        if (t + s + d + e == 15) {
            i++;
            cout << g << endl;
        }
    }
    cout << "Quintity = " << i;
    return 0;
}