Double Negation in C++

Question

I just came onto a project with a pretty huge code base.

I\'m mostly dealing with C++ and a lot of the code they write uses double negation for their boolean logic.

Answer 1

If variable is of object type, it might have a ! operator defined but no cast to bool (or worse an implicit cast to int with different semantics. Calling the ! operator twice results in a convert to bool that works even in strange cases.