Re: += operation

From:

=?UTF-8?B?RXJpayBXaWtzdHLDtm0=?= <Erik-wikstrom@telia.com>

Newsgroups:

comp.lang.c++

Date:

Sat, 14 Jun 2008 19:13:55 GMT

Message-ID:

<TLU4k.144$U5.391@newsb.telia.net>

On 2008-06-14 18:20, foolsmart2005@gmail.com wrote:

ComplexNum ComplexNum::operator +(const ComplexNum& rhs) const //
- operation is the similar way
{
   ComplexNum ans;
   ans.real = real + rhs.real;
   ans.imaginary = imaginary + rhs.imaginary;
   return ans;
}

it works and my lecturer said it is correct but,
for += operation, my code is:
ComplexNum ComplexNum::operator += (const ComplexNum& rhs) const
{
           ComplexNum ans;
           ans.real += rhs.real;
           ans.imaginary += rhs.imaginary;
           return ans;
}

here is lecturer's comment:
+= should be different. a += b means a = a + b
therefore *this object (i.e. a) should be updated with the answer.

Do anyone know how to write += operation?

In the += case you want to add the values in rhs to the values of the
complex number on the left hand side (which will be "this" in the body
of the += operator. The += operator should also return a reference to
the number on the left hand side instead of a new object containing the
value of the operation.

--
Erik Wikstr??m