When should a member function have a const qualifier and when shouldn't it?

Question

About six years ago, a software engineer named Harri Porten wrote this article, asking the question, \"When should a member function have a const qualifier and when shouldn\'t i

Answer 1

when it doesn't modify the object.

It simply makes this to have type const myclass*. This guarantees a calling function that the object won't change. Allowing some optimizations to the compiler, and easier for the programmer to know if he can call it without side effects (at least effects to the object).