kakoe-to zadanie

#include <iostream>
using namespace std;
int main() {
int a, b, c, d, s;
for(int n = 1000; n<10000;) {
    a=n/1000;
    b=n/100%10;
    c=n/10%10;
    d=n%10;
    s=a+b+c+d;
    if(s==15){
        cout << n << endl;
        n++;
        }
        else {
        n++;
        }
    }
return 0;
}