Design Patterns in C++

Creational Creational patterns are ones that create objects for you, rather than having you instantiate objects directly. This gives your program more flexibility in deciding which objects need to be created for a given case.
Abstract Factory Abstract Factory groups object factories that have a common theme. The AbstractFactory adds the basic ideas of the FactoryMethod:
  1. Assign the responsibility for creating objects that belong together to one class.
  2. Define a basic abstract type, so one can decide on the fly, which special set of sub-classes to be produced.
Builder Builder constructs complex objects by separating construction and representation.
Factory Method Factory Method creates objects without specifying the exact class to create.
Prototype creates objects by cloning an existing object.
Singleton Singleton restricts object creation for a class to only one instance.
Structural These concern class and object composition. They use inheritance to compose interfaces and define ways to compose objects to obtain new functionality.
Adapter Adapter allows classes with incompatible interfaces to work together by wrapping its own interface around that of an already existing class.
Bridge Bridge decouples an abstraction from its implementation so that the two can vary independently.
Composite Composite composes zero-or-more similar objects so that they can be manipulated as one object.
Decorator Decorator dynamically adds/overrides behaviour in an existing method of an object.
Facade Facade provides a simplified interface to a large body of code.
Flyweight Flyweight reduces the cost of creating and manipulating a large number of similar objects.
Proxy Proxy provides a placeholder for another object to control access, reduce cost, and reduce complexity.
Behavioral Most of these design patterns are specifically concerned with communication between objects.
Chain of responsibility Chain of responsibility delegates commands to a chain of processing objects.
Command Command creates objects which encapsulate actions and parameters.
Interpreter Interpreter implements a specialized language.
Iterator Iterator accesses the elements of an object sequentially without exposing its underlying representation.
Mediator Mediator allows loose coupling between classes by being the only class that has detailed knowledge of their methods.
Memento Memento provides the ability to restore an object to its previous state (undo).
Observer Observer is a publish/subscribe pattern which allows a number of observer objects to see an event.
State State allows an object to alter its behavior when its internal state changes.
Strategy Strategy allows one of a family of algorithms to be selected on-the-fly at runtime.
Template Template method defines the skeleton of an algorithm as an abstract class, allowing its subclasses to provide concrete behavior.
Visitor Visitor separates an algorithm from an object structure by moving the hierarchy of methods into one object.