Hello All, This is my first post in the forum. And I'm also comparatively new to C++. So accept my apologies in advance if I dont sound like a noob and make you tickle :happy: SO..I've been studying and teaching C++ for around 2 years now. But just a few days back I found some new terms which I have never seen associated with C++. So kindly put some light on these topics for me. I'm much grateful. The topics are as follows : 1. Economy of Expression (I read this term in "The C Programming Language" on the very first line but still couldnt relate it.) 2. Concept of common mechanism 3. How to identify a common mechanism 4. How do the concepts of Common Mechanism and virtual methods combine to give Polymorphic behavior 5. Do’s and Don’ts of developing a class hierarchy 6. How to design the Root class of the hierarchy 7. How to design package structure of an application