How to change compiler in Xcode C ++

Question

I have been looking for quite a while, and I cannot figure out how to change the compiler in the latest Xcode. I am not sure if it is currently installed, but I would like to change it to GCC, if possible. Right now, my homework example does not recognize ptrace.h, so I think it might be due to the selected compiler.

Answer 1

Screenshot of assembly rules:

You can add a rule for C ++, click "+" to the right of "Custom".

Answer 2

Select the project in the browser, then go to ...