How to use nested for loop for a pattern?

[aa3685]

What is an example code for a pattern?

[Ganado]

// Example program
#include <iostream>

int main()
{
    for (int y = 0; y < 4; y++)
    {
        for (int x = 0; x < 5; x++)
        {
            std::cout << ((x - y < 1) ? 0 : 1);
        }
        std::cout << "\n";
    }
}