Example of design patterns
Eric Gamma, Richard Helm, Ralph Johnson and John Vlissides wrote in 1995, "Design Patterns: They released the book "Elements of Reusable Object-Oriented Software". These four are also known as "The Four Gangs".
Creational -They guide the creation of objects in the software system -Factory Method -Singleton -Abstract Factory -Builder
Structural -It is the pattern that shows the relations of objects in the software system with each other. -Adapter -Decorator -Facade -Proxy
Behavioral -It is the pattern that follows the behavior of objects. -Iterator -Observer -Memento -Mediator