CODE EXAMPLE FOR SWIFT

protocol oriented programming

///what does protocol extension allows us to do in swift
///it allow to create default function for protocol
protocol Greeting {
    func sayHello()
}


extension Greeting {
    func sayHello() {
        print("Hello World")
    }
}


class SimpleGreeting: Greeting { //No need to impliment the function
    
}

class WishesGreeting: Greeting {
    func sayHello() {
        print("Hello World this is new year")
    }
}


//Other way to create option protocol
@objc protocol ObjcGreeting {
  @objc optional func sayHello()
}


class ObjcSimpleGreeting: ObjcGreeting { //No need to impliment the function
    
}

class ObjcWishesGreeting: ObjcGreeting {
    func sayHello() {
        print("Hello World this is new year")
    }
}




class ProtocolOrientedProgrammingViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        
        self.view.backgroundColor = .white

        let wishesGreeting = WishesGreeting();
        wishesGreeting.sayHello()
        
    }
}