How to make the mod of a negative number to be positive?

Question

Basically, I need (-3) % 5 to be "2" instead of "-3". Python produces "2", but C++ produces "-3". Not sure how to produce "2" in C++. Thanks!

Answer 1

Most easily: ((x % 5) + 5) % 5

Answer 2

Add the base if the input number X is negative:

X % Y + (X % Y < 0 ? Y : 0);