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c++operator-overloading
SE Does Not Like Dissent
SE Does Not Like Dissent

Reputation: 1815

C++ class operator overloading

It's possible to overload the not operator for a class:

class TestA
{
    public:
       bool Test;
       const bool operator!(){return !Test;}
};

So that...

TestA A; A.Test = false;
if(!TestA){ //etc }

...can work. However, how does the following work?

if(TestA) //Does this have to be overloaded too, or is it the not operator inverted?

I will add, having read it, I am slightly confused by the typedef solution that is employed, and I don't fully understand what is occurring, as it seems somewhat obsfucated. Could someone break it down into an understandable format for me?

Upvotes: 2

Views: 267

Answers (2)

arne
arne

Reputation: 4674

You could write an operator bool(). This takes care of coercion to bool, making statements as your above one possible.

Upvotes: 4

Mark B
Mark B

Reputation: 96233

You overload operator void* (like the standard library's iostreams) or use boost's trick of using an "unspecified_bool_type" typedef (safe bool). It does NOT automatically invert your operator!

Upvotes: 2

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