OO Design Principle roundup...

I have listed a set of key design principles here for OO.

Design Principle: A design principle is a basic tool or technique that can be applied to designing and writing code to make that code more maintainable, flexible or extensible.

Principle #1: The Open-Closed Principle(OCP)
Classes should be open for extension but closed for modification.

thanks lester
Keep them coming

Here come the other principles in OOAD. We will discuss on each of them in detail later.

Principle #2: The Don't Repeat Yourself Principle (DRY)
Avoid duplicate code by abstracting out things that are common and placing those things in a common location.

Principle #3: The Single Responsibility Principle (SRP)
Every object in your system should have a single responsibility, and all the object's services should be focussed on carrying out that single responsibility.

Principle #4: The Liskov Substitution Principle (LSP)
Subtypes must be substitutable for their base types.