Design Patterns

a) Creational pattern:

1) Singleton Pattern 		- Ensures only one instance of a class is created.
2) Factory Method pattern	- Creates objects without specifying the exact class.
3) Abstract Factory pattern- Creates families of related objects without specifying their concrete classes.
4) Builder pattern			- Constructs complex objects step by step.
5) Prototype pattern		- Creates new objects by cloning existing ones.

b) Structural pattern:

1) Adapter pattern			- Converts the interface of a class into another interface clients expect.
2) Bridge pattern			- Decouples an abstraction from its implementation, allowing them to vary independently.
3) Composite pattern		- Composes objects into tree structures and treats them uniformly.
4) Decorator pattern		- Dynamically adds additional behavior to an object.
5) Facade pattern			- Provides a simplified interface to a complex subsystem.
6) Flyweight pattern		- Minimizes memory usage by sharing common state between multiple objects.
7) Proxy pattern			- Provides a placeholder for another object to control access to it.

c) Behavioral pattern:

1) Observer pattern			- Notifies multiple objects about state changes in an object.
2) Strategy pattern			- Encapsulates interchangeable algorithms and allows them to be easily swapped.
3) Chain of Responsibility pattern - Chains objects together to process a request sequentially.
4) Command pattern			- Chains objects together to process a request sequentially.
5) Iterator pattern			- Provides a way to access elements of an aggregate object sequentially.
6) State pattern			- Alters an object's behavior based on its internal state.
7) Template Method pattern	- Defines the skeleton of an algorithm, allowing subclasses to provide specific implementations.
8) Visitor pattern			- Separates the algorithms from the objects they operate on, allowing new operations to be added without modifying the objects.
9) Mediator pattern 		- Defines an object that encapsulates communication and coordination between other objects
10) Memento pattern 		- Captures and stores the internal state of an object
11) Interpreter Pattern 	- Defines a representation of grammar and interprets sentences in that grammar

d) Architectural pattern:

1) Model-View-Controller (MVC) pattern	 - Separates an application into three interconnected components: Model, View, and Controller.
2) Model-View-Presenter (MVP) pattern	 - Separates an application into three components: Model, View, and Presenter, similar to MVC but with a different interaction pattern.
3) Model-View-ViewModel (MVVM) pattern 	 - Separates an application into three components: Model, View, and ViewModel, often used in GUI applications.