Re: operator= function

From:

"Victor Bazarov" <v.Abazarov@comAcast.net>

Newsgroups:

comp.lang.c++

Date:

Tue, 4 Dec 2007 10:46:19 -0500

Message-ID:

<fj3sod$h02$1@news.datemas.de>

Rahul wrote:

Hi Everyone,

I was just overloading operator = for a class and i have a problem in
one case...

class A
{
A& operator=(const A& obj)
{
   return *this;
  // please ignore the logic of this function
}
};

int main()
{
A a,b
a = b; //works fine
if(a=b) // causes compile time error as the operator=() returns a
reference to A and not a BOOL.
  {
   printf("both the objects are the same\n");
  }
else
  {
   printf("both the objects are different\n");
  }
}
return(0);
}

Now, i tried to overload operator=() function, but overloading just
based on the return type doesn't make sense.
So is there anyway to solve this problem, so that the user of the
class can get to work in both the cases just like any built in type?

A simple way would be to *also* provide a conversion function to type
'bool' in your 'A' class:

    class A {
        ...
        operator bool() const { return true; }
    };

Or any other conversion function that yields a type that can be used
in a logical expression.

Now, let me ask you, why do you think you need assignment in the 'if'
expression

    if (a = b)

instead of comparison

    if (a == b)

? Or did you not know that those are two different operators?

V
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