?
Solved

What does it mean to assign zero to a function?

Posted on 2013-06-10
4
Medium Priority
?
298 Views
Last Modified: 2013-06-10
class Socket
{
  public:
   ...
   ..
   virtual ~Socket() {};

    virtual signed int close    () = 0;



What does it mean to assign 0 to close()?
0
Comment
Question by:naseeam
  • 2
  • 2
4 Comments
 
LVL 86

Assisted Solution

by:jkr
jkr earned 1000 total points
ID: 39235984
It means that 'close()' is declared as a so called 'pure virtual' function, i.e. is expected to be overridden by a derived class. You cannot instantiate a class that has any pure virtual functions, they serve as a "interface definition". See also http://www.exforsys.com/tutorials/c-plus-plus/c-pure-virtual-function-and-base-class.html
0
 
LVL 1

Author Comment

by:naseeam
ID: 39235999
class Socket
{
  public:
   ...
   ..
   virtual ~Socket() {};

    virtual signed int close    () = 0;


   /* Is this also pure virtual fucntion?  Will this be overridden by derived class
      as well. */
   virtual signed int openWait () {return SocketErrorValue_None;}
0
 
LVL 86

Accepted Solution

by:
jkr earned 1000 total points
ID: 39236023
No, this funtion is virtual, not "pure virtual". That means you canoverwrite it, but - as opposed to "pure virtual" - you don't have to.
0
 
LVL 1

Author Closing Comment

by:naseeam
ID: 39236196
Excellent concise answers!  Short but complete.

Great link on C++ training.  Thank you so much!
0

Featured Post

Never miss a deadline with monday.com

The revolutionary project management tool is here!   Plan visually with a single glance and make sure your projects get done.

Question has a verified solution.

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

Go is an acronym of golang, is a programming language developed Google in 2007. Go is a new language that is mostly in the C family, with significant input from Pascal/Modula/Oberon family. Hence Go arisen as low-level language with fast compilation…
Basic understanding on "OO- Object Orientation" is needed for designing a logical solution to solve a problem. Basic OOAD is a prerequisite for a coder to ensure that they follow the basic design of OO. This would help developers to understand the b…
The viewer will learn how to use the return statement in functions in C++. The video will also teach the user how to pass data to a function and have the function return data back for further processing.
The viewer will be introduced to the member functions push_back and pop_back of the vector class. The video will teach the difference between the two as well as how to use each one along with its functionality.

593 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