Design Patterns

Design patterns provide general solutions to software design problems we find in real-world application development.

Before starting with design patterns let's understand what the meaning of design patterns and why they are useful in software programming/architecture.

"Each pattern describes a problem that occurs over and over again in our environment, and then describes the core of the solution to that problem, in such a way that you can use this solution a million times over, without ever doing it the same way twice." - Christopher Alexander, A Pattern Language.

It is important to understand design patterns rather than memorizing their classes, methods and properties. First identify the software design problem then see how to address these problems using design patterns and determine the best suited design problem to solve the problem.

There are 23 design patterns, also known as Gang of Four (GoF) design patterns. The Gang of Four are the authors of the book, "Design Patterns: Elements of Reusable Object Oriented Software".