simple override question

[StaticPhilly]

hello,

OK i need a little help,

i want to override a funtion from a parent class, but i can seem to get it to work,

so i have a layout the same as below, i want to override the Z function from class A in class B.
when i use this layout below it still calls the Z function from A rather than B, i am creating the object from B so from my understanding it should be overwrote...

can anyone help me out with this?

thanks
Philly

Class A Header:

#pragma once

class A
{
private:
    void Y();
protected:
    virtual void Z();
};

class A Source:

#include "stdafx.h"
#include "A.h"

void A::Y()
{
    this->Z();
}

void A::Z()
{
    // want to override this in class B;
}

Class B Header

#pragma once
#include "A.h"

class B : A
{
protected:
    void Z();
};

Class B Source:

#include "stdafx.h"
#include "B.h"

void B::Z()
{
    // Do Somthing Here!
}

[VictorN]

1. Why don't you declare void Z() in class B as a virtual?
2. Where and how do you call "the Z function from A rather than B..."?

[StaticPhilly]

its unmanaged c++ (not clr or mfc)

the reason behide void Z not being virtual in B is because its not the parent function but rather a function to override its parent. i would only have to declare it as virtual in class B if i was going to override class B::Z as well.

the reason for Z being called from class A is that class A dose all the hard work before calling,
the whole idea in making a parent class (class A) is so i dont have to duplicate my code everywere, insted just override what i need to.
just to make this a bit more clear,

class A:
void Start(), creates a new thread to StartProcessing
void StartProcessing(), dose some work then passes the data to ProcessCommand
bool ProcessCommand(string command), this is what i want to override and is virtual

class B:
bool ProcessCommand(string command), this is the override and is not virtual

My Usage:
B* test = new B();
B->Start();

[VictorN]

Neither of your posts does contain any example of using these virtual methods. So how do you expect we could help you if we cannot test/reproduce your problem?

[StaticPhilly]

Class A:

protected: virtual bool ProcessCommand(string, string);
public: static void StartProcessing(PVOID);

void TCPSession::StartProcessing(void* Link)
{
	// Create TCPSession base from link
	TCPSession* base = (TCPSession*)Link;

	// Start Receaving...
	base->_TCPReceiveBuffer->Start();

	// Welcome
	base->_TCPSocket->SendData("+OK Welcome!\r\n");

	// String var
	string CommandLine;
	size_t CommandSize;
	size_t CommandSplitPosision;
	string Command;
	string CommandParameter;

	while (true)
	{
		if (base->_TCPReceiveBuffer->DataAvilable())
		{
			// Read the command
			CommandLine = base->_TCPReceiveBuffer->ReadLine();

			// Get the command size and split posision 
			CommandSize = CommandLine.size();
			CommandSplitPosision = CommandLine.find_first_of(" ");

			// get the command and parameter if passed
			if (CommandSplitPosision == -1)
			{
				Command = CommandLine;
				CommandParameter = "";
			} else {
				Command = CommandLine.substr(0, CommandSplitPosision);
				CommandParameter = CommandLine.substr(CommandSplitPosision, CommandSize);
			}

			// Convert the command to upper case
			Misc::StrToUpper(Command);

			// Process
			if (base->ProcessCommand(Command, CommandParameter))
			{
				break;
			}

		}
		Sleep(100);
	}

	base->_TCPReceiveBuffer->Stop();
	base->_TCPSocket->Close();
	delete[] base;
}

bool TCPSession::ProcessCommand(string command, string parameter)
{
	if (command == "QUIT")
		return true;
	return false;
}

Class B:

protected bool ProcessCommand(string, string);

bool RAPSession::ProcessCommand(string Command, string Parameter)
{
	if (Command == "QUIT")
	{
		this->Quit(); 
		return true;
	}

	return false;
}

void RAPSession::Quit()
{
	this->_TCPSocket->SendData("+OK Good-Bye\r\n");
}

[VictorN]

There is no any attempt to access/call RAPSession::ProcessCommand in the code snippet you have posted.
You only call the TCPSession::ProcessCommand method.

[StaticPhilly]

yes i was affraid it would be that,

is there any way round this without overriding my StartProcessing() to tell it to call the new ProcessCommand function

[VictorN]

is there any way round this without overriding my StartProcessing() to tell it to call the new ProcessCommand function

What do mean by "the new ProcessCommand function"? Perhaps, you meant RAPSession::ProcessCommand?
Yes it would be possible if the object calling it were of the type RAPSession rather than TCPSession

[StaticPhilly]

thanks for your help VictorN i do apreashate it,

i am a little confused tho,

because,
Im going to have 4 classes that enherit TCPSession class,
I dont really want to implant a new TCPSession::StartProcessing function into all my classes (thats what calls the TCPSession::ProcessCommand that i was wanting to override)
and with project going to have 4 classes that inherit TCPSession its not as simple as just changing the call in TCPSession::StartProcessing.

so im still ratting my brain on how to do this,
starting to think along the lines of adding a new function to TCPSession to set a private var (TCPSession* _child), get TCPSession::ProcessCommand to use that _child to call the ProcessCommand and then finerly in my classes that enherit TCPSession call that function to set the var to its self. somthing like SetChild((TCPSession*)this)

[VictorN]

Sorry, but I couldn't understand anything from your explanation.
So I think I should give up...