What are types of protocols in swift?

 What are the types of protocols in swift?

Swift is a powerful and modern programming language for developing iOS, macOS, watchOS, and tvOS applications. It is built with the principles of Object-Oriented Programming (OOP) in mind. One of the essential concepts in OOP is the use of protocols. Protocols define a blueprint or a set of rules that a class or a struct can conform to. This concept allows for better code organization, reusability, and modularity

In Swift, there are four types of protocols:

1. Class-Only Protocols: A Class-Only protocol is a protocol that can only be adopted by a class. It is used to specify the requirements that can only be fulfilled by a class. This protocol type is declared using the keyword “class” instead of the “protocol” keyword. Example:
   

   protocol UIViewController {  
       func viewDidLoad()  
       func viewDidAppear()  
   }  

   The "UIViewController" a protocol is a class-only protocol because the view controller class can only conform to it.
2. Protocol Inheritance: Protocol inheritance is a way of defining a new protocol that inherits the properties of an existing protocol. In other words, it is a way of extending an existing protocol. This concept helps to organize code and avoid duplication of code.

Example:


protocol Bird {  
    func fly()  
}  
protocol Penguin: Bird {  
    func swim()  
}  

 Here, the "Penguin" protocol inherits the properties of the "Bird" protocol, which means that it has access to the "fly()" function. Additionally, the "Penguin" protocol defines a new requirement "swim()". 
3. Protocol Composition: Protocol composition is a way of combining two or more protocols into a single requirement. This concept helps to create more concise and focused protocols that are easier to manage.

Example:

protocol Flyable {  
    func fly()  
}  
protocol Walkable {  
    func walk()  
}  
typealias Bird = Flyable & Walkable     

Here, the "Bird" the protocol is a combination of two protocols: "Flyable" and "Walkable". This means that any class or struct that conforms to the "Bird " the protocol must implement the "fly()" and "walk()" functions.

4. Associated Types: Associated types are used to define a placeholder type within a protocol. This concept allows a protocol to be flexible and accommodate different types of data. Associated types are declared using the keyword “associatedtype”.

Example:

protocol Container {  
    associatedtype Item  
    func add(item: Item)  
} 

Here, the "Container" the protocol defines an associated type "Item", which means that any class or struct that conforms to the "Container" the protocol must declare its own version of the "Item" type.

In conclusion, protocols are an essential part of Swift programming. They help to organize code, increase reusability, and create more modular applications. By understanding the different types of protocols in Swift, developers can create more concise and focused protocols that are easier to manage.




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