Please search for a^2+b^2=2c^2 in most recent code playgrounds

No problem, if others can understand. please tell me

Youre not telling your for loops what the variables a, b, c are to start, ie you haven't initialized them. Set them to 0 so for(int a = 0; a < 10; a++) and so on.

It ran. Thanks very much James.

sorry I don't know that !