Operator function for object pointers

[kenkahn]

I define a class "class xxx" with the following operator override:

class xxx {
int xxx:perator==(const xxx &ptr) const;
}

So if I define

xxx A;
xxx B;

I can do stuff like

if (A == B) {};

My question is what if instead I have

xxx *A_ptr = new xxx;
xxx *B_ptr = new xxx;

How do I define the operator override to work on object pointers
instead of by reference.

if (A_Ptr == B_ptr) {}

 

[Victor Bazarov]

I define a class "class xxx" with the following operator override:

class xxx {
int xxx:perator==(const xxx &ptr) const;
}

So if I define

xxx A;
xxx B;

I can do stuff like

if (A == B) {};

My question is what if instead I have

xxx *A_ptr = new xxx;
xxx *B_ptr = new xxx;

How do I define the operator override to work on object pointers
instead of by reference.

if (A_Ptr == B_ptr) {}

You cannot redefine operators for built-in types, and pointers are
built-in types.

Do
if (A_Ptr && B_Ptr && *A_Ptr == *B_ptr) {}

V

 

[Jorgen Grahn]

I define a class "class xxx" with the following operator override:

class xxx {
int xxx:perator==(const xxx &ptr) const;
}

Two errors and a very unfortunate name in three lines. You mean

class xxx {
// public and so on ...
bool operator== (const xxx& other) const;
};

/Jorgen

 

[James Kanze]

kenkahn wrote:

[...]

You cannot redefine operators for built-in types, and pointers are
built-in types.

The important point, of course, is that the above expression
already has a defined semantics. With very few exceptions
(unary operator&), you can't change defined semantics.

Do
if (A_Ptr && B_Ptr && *A_Ptr == *B_ptr) {}

if ( A_Ptr == NULL
? B_Ptr == NULL
: B_Ptr != NULL && *A_Ptr == *B_Ptr ) {}



Most of the time, I think I'd go with a function call.

(PS: I'm not saying that your response was wrong. Since he
didn't say what the semantics were supposed to be, we don't
know. Most of the time I'm dealing with pointers, the built-in
semantics are what I want.)