What the code does when I use for(){for(){}}

Question

I want to know what the code does when I use this sintax
for(a =0; a <b; a++){
for (c = a +1; c <b; c++){
statment;
}
}

Answer 1

https://code.sololearn.com/c0LpzDJxoupU/#c

let b = 6 (in my code).
You can modify to check the differencies..

Answer 2

So its looks like you fix the first loop, and run the Second loop? Right? , or in another words, u fix the first loop, run the Second, add one unit to the first loop, and run the second?