如何在c++中检查一个数字是否能被2*M_PI整除?

This is what I've done for checking the divisibility of a number by 2*M_PI. "w" is a constant that's 2/3 and t is the variable that varies by t += dt, where dt is 0.1. I'm trying to use the mod operator, %, to see if something is divisible. But its not working.This is what I've done for checking the divisib