Swift -- protocol、extension

protocol ExampleProtocol{

var simpleDescription:String{get}

mutating func adjust()

}

class SimpleClass:ExampleProtocol{

var simpleDescription:String = "A very simple class"

var anotherProperty:Int = 69105

func adjust(){

simpleDescription += " Now 100% requested"

}

}

var a = SimpleClass()

print(a.simpleDescription)

a.adjust()

print(a.simpleDescription)

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protocol tcpprotocol {
init(aprot: Int)
}
class tcpClass: tcpprotocol {
required init(aprot: Int) {
}
}
// 使用required修饰符可以保证：所有的遵循该协议的子类，同样能为构造器规定提供一个显式的实现或继承实现。
// 如果一个子类重写了父类的指定构造器，并且该构造器遵循了某个协议的规定，那么该构造器的实现需要被同时标示required和override修饰符：
protocol tcpprotocol {
init(no1: Int)
}
class mainClass {
var no1: Int // 局部变量
init(no1: Int) {
self.no1 = no1 // 初始化
}
}
class subClass: mainClass, tcpprotocol {
var no2: Int
init(no1: Int, no2 : Int) {
self.no2 = no2
super.init(no1:no1)
}
// 因为遵循协议，需要加上"required"; 因为继承自父类，需要加上"override"
required override convenience init(no1: Int) {
self.init(no1:no1, no2:0)
}
}
let res = mainClass(no1: 20)
let show = subClass(no1: 30, no2: 50)
print("res is: \(res.no1)")
print("res is: \(show.no1)")
print("res is: \(show.no2)")

******************************************

struct SimpleStructure:ExampleProtocol{

var simpleDescription:String = "A simple structure"

mutating func adjust(){

simpleDescription += " (adjust)"

}

}

var b = SimpleStructure()

print(b.simpleDescription)

b.adjust()

print(b.simpleDescription)

extension Int:ExampleProtocol{

var simpleDescription:String{

return "The number is \(self)"

}

mutating func adjust(){

self += 50

}

}

println(7.simpleDescription)

extension String:ExampleProtocol{

var simpleDescription:String{

return "My name is \(self)"

}

mutating func adjust(){}

}

print("XingXing".simpleDescription)