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

One interesting rule of thumb I found while researching this came from here:

A good rule of thumb for LogicalConst is as follows: If an operation preserves LogicalConstness, then if the old state and the new state are compared with the EqualityOperator, the result should be true. In other words, the EqualityOperator should reflect the logical state of the object.