Why do we need design patterns

Question

Why do we need design patterns like Factory, Abstract Factory and Singleton?

Answer 1

Design Patterns provide easy to recognize and use OOP solutions to common problems. They're inherently easy to maintain, because many people are familiar with them. This is very similar to how google works. Everyone knows HOW to google, so when you get a query like "What is the purpose of design patterns", you can very quickly use this common interface to solve a problem.

Design Patterns also solve specific programming challenges regarding usability and maintainability. Pick up the Gang of Four book and have a look at it.

Answer 2

If a problem occurs over and over again, a solution to that problem has been used effectively. That solution is described as a pattern.