Comments on: 12.6 — Pure virtual functions, abstract base classes, and interface classes http://www.learncpp.com/cpp-tutorial/126-pure-virtual-functions-abstract-base-classes-and-interface-classes/ Fri, 29 Aug 2008 19:11:33 +0000 http://wordpress.org/?v=2.5.1 By: Ben http://www.learncpp.com/cpp-tutorial/126-pure-virtual-functions-abstract-base-classes-and-interface-classes/#comment-23072 Ben Thu, 07 Aug 2008 18:55:14 +0000 http://www.learncpp.com/cpp-tutorial/126-pure-virtual-functions-abstract-base-classes-and-interface-classes/#comment-23072 Hi Alex, in your IErrorLog class all functions are private. As i tried to compile your code, with the MySqrt() function, i discoverd, that the compiler complains about that, so i defined a class inheriting IErrorLong and changing the scope of the functions to public; still the compiler insists not to compile the code. So you might want to change the code. Besides that, can you imagine why a virtual class should ever have private member functions? Ben Hi Alex,
in your IErrorLog class all functions are private. As i tried to compile your code, with the MySqrt() function, i discoverd, that the compiler complains about that, so i defined a class inheriting IErrorLong and changing the scope of the functions to public; still the compiler insists not to compile the code. So you might want to change the code. Besides that, can you imagine why a virtual class should ever have private member functions?
Ben

]]> By: Sean http://www.learncpp.com/cpp-tutorial/126-pure-virtual-functions-abstract-base-classes-and-interface-classes/#comment-22328 Sean Wed, 30 Jul 2008 12:15:19 +0000 http://www.learncpp.com/cpp-tutorial/126-pure-virtual-functions-abstract-base-classes-and-interface-classes/#comment-22328 Great tutorial for interface class, Thanks a lot! Great tutorial for interface class,
Thanks a lot!

]]> By: Learn C++ - » 12.5 — The virtual table http://www.learncpp.com/cpp-tutorial/126-pure-virtual-functions-abstract-base-classes-and-interface-classes/#comment-14431 Learn C++ - » 12.5 — The virtual table Mon, 05 May 2008 02:26:37 +0000 http://www.learncpp.com/cpp-tutorial/126-pure-virtual-functions-abstract-base-classes-and-interface-classes/#comment-14431 [...] 2007 Prev/Next Posts « 12.4 — Early binding and late binding | Home | 12.6 — Pure virtual functions, abstract base classes, and interface classes » Friday, February 8th, 2008 at 3:29 [...] [...] 2007 Prev/Next Posts « 12.4 — Early binding and late binding | Home | 12.6 — Pure virtual functions, abstract base classes, and interface classes » Friday, February 8th, 2008 at 3:29 [...]

]]> By: Alex http://www.learncpp.com/cpp-tutorial/126-pure-virtual-functions-abstract-base-classes-and-interface-classes/#comment-11803 Alex Tue, 15 Apr 2008 18:18:28 +0000 http://www.learncpp.com/cpp-tutorial/126-pure-virtual-functions-abstract-base-classes-and-interface-classes/#comment-11803 As far as I know, =0 is just a syntactic convention for letting the compiler know that this is a pure virtual function. You can think about it this way: normal functions have a body of code that needs to be executed when they are called. This code has to live somewhere in memory, so the function's name is essentially a pointer to that code. On the other hand, pure virtual functions have no body, and thus, do not have need for an address at all. 0 is the NULL address. As far as I know, =0 is just a syntactic convention for letting the compiler know that this is a pure virtual function.

You can think about it this way: normal functions have a body of code that needs to be executed when they are called. This code has to live somewhere in memory, so the function’s name is essentially a pointer to that code.

On the other hand, pure virtual functions have no body, and thus, do not have need for an address at all. 0 is the NULL address.

]]> By: Susan http://www.learncpp.com/cpp-tutorial/126-pure-virtual-functions-abstract-base-classes-and-interface-classes/#comment-11691 Susan Mon, 14 Apr 2008 08:58:27 +0000 http://www.learncpp.com/cpp-tutorial/126-pure-virtual-functions-abstract-base-classes-and-interface-classes/#comment-11691 Can you please answer why a pure virtual function should be equated to 0 and not to any other number. Can you please answer why a pure virtual function should be equated to 0 and not to any other number.

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