Want to protect your cyber security and still get fast solutions? Ask a secure question today.Go Premium

x
?
Solved

user defined assignment

Posted on 2002-06-12
3
Medium Priority
?
282 Views
Last Modified: 2010-04-02
I would love to have a user defined copy function
like this one.

void operator=(RGBQUAD& q, PALETTEENTRY& pe)
{
  q.rgbRed = pe.peRed;
  q.rgbGreen = pe.peGreen;
  q.rgbBlue = pe.peBlue;
  q.rgbReserved = 0;
  }

but to compiler tells me to bugger off.
Is "void Copy(RGBQUAD& q, PALETTEENTRY& pe)"
my only option? Thanks.

0
Comment
Question by:GGRUNDY
3 Comments
 
LVL 9

Accepted Solution

by:
jasonclarke earned 200 total points
ID: 7075017
An assignment operator must be a member function of a class... it is an operator that works on an existing class instance.
 
Try adding it to your RGBQUAD class/struct, like this:

class RGBQUAD
{
//...

    RGBQUAD& operator=(const PALETTEENTRY& pe)
    {
       rgbRed = pe.peRed;
       rgbGreen = pe.peGreen;
       rgbBlue = pe.peBlue;
       rgbReserved = 0;
       return *this;
    }

};
0
 
LVL 22

Expert Comment

by:nietod
ID: 7075127
FYI the reason for this, is because you cannot write an assignment to one of the built-in types.  i.e. it is to prevent you from doing things like

int &operator = (int l, int r);
int operator = (int l, double r);

which have already been defined by the language.  


Note how Jason changed the return value of your function.     This is not required, but it is a customary practice.  by doing that you can "chain" assignments like

a = b = c;
0
 
LVL 3

Author Comment

by:GGRUNDY
ID: 7075343
Thanks guys.
0

Featured Post

What does it mean to be "Always On"?

Is your cloud always on? With an Always On cloud you won't have to worry about downtime for maintenance or software application code updates, ensuring that your bottom line isn't affected.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Unlike C#, C++ doesn't have native support for sealing classes (so they cannot be sub-classed). At the cost of a virtual base class pointer it is possible to implement a pseudo sealing mechanism The trick is to virtually inherit from a base class…
Written by John Humphreys C++ Threading and the POSIX Library This article will cover the basic information that you need to know in order to make use of the POSIX threading library available for C and C++ on UNIX and most Linux systems.   [s…
The viewer will learn additional member functions of the vector class. Specifically, the capacity and swap member functions will be introduced.
The viewer will be introduced to the technique of using vectors in C++. The video will cover how to define a vector, store values in the vector and retrieve data from the values stored in the vector.
Suggested Courses

580 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question