Multiple Inheritance Classes

Class NC_PROTO_TELNET: public NC_TELNET_MSP, public NC_TELNET_MXP, public NC_TELNET_MCP{
/*

*/
}

In ur explanation replace : by , . Then it will work fine. Is it all u want to know?

Be aware of the diamond problem ( http://en.wikipedia.org/wiki/Diamond_problem) that can arise.

http://www.parashift.com/c++-faq-lite/multiple-inheritance.html

Sorry, my bad, then. I must have misread you initial post.

Just a funny way to drive Graham's point home....

In the book by Stroustrup, "The Design and Evolution of C++", on the chapter about multiple inheritance, he gave the rational for the notion as a quote from some message board (if memory serves correctly) with:

"Because I have both a father and a mother."

Right, so, be careful not to let an object marry it's sister!

The kids just don't come out right :)

Isn't that upside down? Would it not be better for NC_PROTO_TELNET to be an abstraction of the other three, and those others to be implementations of it?

Do the MSP, MXP and MCP classes all have entirely different interface (i.e. no non-private member functions in common)? If they share interface, then doing it this way, you'll hit the Siamese twin problem, and anyway, shared interface suggests that the PROTO class should be and abstraction, not a derivative.

In my opinion from the little I know, I agree with you Graham. I think that the NC_PROTO_TELNET class from what he describes should be an abstract base class that shares an interface for the other protocols, and then to handle any one of these protocols seamlessly, a proxy class that holds a pointer to a NC_PROTO_TELNET object, which could point at the derived class objects. :D

In fact, this design pattern is very OOP, and is very useful. So useful, I have got some real big thoughts as to why the programmers of the standard libraries do not follow this design pattern.

You think about OOP in terms of abstraction, polymorphism, encapsulation, blackboxing, etc... The list goes on and on. However, if you take a look at the design pattern mentioned, you take advantage of "IS A" and polymorphism where the proxy class calls the virtual functions. :cool:

OK. Fair enough.