Originally Posted by drdebcol View Post
I have never seen this "public virtual" declaration !
What is it basically ?
That's what the article is about. The 4th code example shows you what public inheritance is, and there are two other types of inheritance: private and protected.

The 5th code example shows you what multiple inheritance is and why you need "virtual" in there if you have multiple inheritance from classes that themselves share the same base class. If you have Base, and Derived1 and Derived2 derived from Base, and Derived3 derived from Derived1 and Derived2, then Derived3 will contain 2 Base's (Derived1's and Derived2's).