[Swift] Class

Property

need the initial value.

• initial value
• Initialize to init
• optional variable, constant

// 1.
class Man {
    var age: Int = 0
    var weight: Double = 0.0
}

// 2.
class Man {
    var age: Int?
    var weight: Double!
}

// 3.
class Man {
    var age: Int = 1
    var weight: Double = 3.5
    func display() {
        print("Age=\(age), Weight=\(weight)")
    }
}
var kim = Man()
kim.display()

Class or Type method

class Man {
	var age: Int = 1
	var weight: Double = 3.5
	func display() {
		print("Age = \(age), Weight = \(weight)")
	}
	class func cM() {
		print("cM is class method")
	}
	static func scM() {
		print("scM is class method(static)")
	}
}

var kim = Man()
kim.display()
Man.cM()
Man.scM()

Class methods created with class keywords can be overridden by child classe

init()

• constructor

int() {
}

class Man {
	var age: Int = 1
	var weight: Double = 3.5
	func display() {
		print("Age = \(age), Weight = \(weight)")
	}
	init(yourAge: Int, yourWeight: Double) {
		age = yourAge
		weight = yourWeight
	} // designated initializer
}

var kim = Man(yourAge: 10, yourWeight: 10.5)
kim.display()

Self

class Man {
	var age: Int
	var weight: Double
	func display() {
		print("Age = \(age), Weight = \(weight)")
	}
	init(age: Int, weight: Double) {
		self.age = age
		self.weight = weight
	} // designated initializer
}

var kim = Man(age: 10, weight: 10.5)
kim.display()

Stored property and Computed property

class Man {
	var age: Int = 1 // stored property
	var weight: Double = 3.5 // stored property
	var koreanAge: Int { // computed property
		get {
			return age + 1
		}
	}
	func display() {
		print("Age = \(age), Weight = \(weight)")
	}
	init(age: Int, weight: Double) {
		self.age = age
		self.weight = weight
	} // designated initializer
}

var kim = Man(age: 10, weight: 20.5)
print(kim.koreanAge)

Getter

• If there is no setter, get{} can be omitted.

class Man {
	var age: Int = 1 
	var koreanAge: Int {
		get {
			return age + 1
		}
}

class Man {
	var age: Int = 1
	var koreanAge: Int {
		return age + 1
  }
}

Setter

class Man {
	var age: Int = 1
	var weight: Double = 3.5
	var koreanAge: Int {
		get {
			return age + 1
		}
		set(internationalAge) {
		  age = internationalAge + 1
		}
	}
	func display() {
		print("Age = \(age), Weight = \(weight)")
	}
	init(age: Int, weight: Double) {
		self.age = age
		self.weight = weight
	} // designated initializer
}

var kim = Man(age: 10, weight: 20.5)
print(kim.koreanAge) // 11, call getter
kim.koreanAge = 2 // call setter
print(kim.age) // 3

• newValue

class Man {
	var age: Int = 1
	var weight: Double = 3.5
	var koreanAge: Int {
		get { return age + 1	}
		set { age = newValue + 1 } // Shorthand Setter Declaration
	}
}

Method overloading

class Man {
	var age: Int = 1
	var weight: Double = 3.5
	func display() {
		print("Age = \(age), Weight = \(weight)")
	}
	init(age: Int, weight: Double) { // 1
		self.age = age
		self.weight = weight
	}
	init(age: Int) { // 2
		self.age = age
	}
}

var kim : Man = Man(age: 10, weight: 20.5) // 1
var kim2 : Man = Man(age: 30) // 2
kim.display()
kim2.display()