Nested for

#include <iostream>
using namespace std;

int main (){
    int i, j;

    for (int i=1; i<=7; i++){
        for (int j=i; j>0; --j){
            cout << j;
        }
        cout << "\n";
    }
}

/*
1
21
321
4321
54321
654321
7654321
*/