Swift's inheritance and initialization of the struct body

/*

Swift's inheritance

If you want to override the storage properties of the parent class

1. After rewriting, you can add property observers to it. Column One:

2. You can change it to a calculated attribute (but not the original function of the Parent property). Column two:

3. The parent class is read-only (get, or let), and the subclass cannot add a property observer. Column three:

If you override the computed property of the parent class

1. The parent-Class computed property is read-only and can be overridden by subclasses to add the Seter method. Column four:

Method inheritance. Column Five:

*/

Column One:

Class Person {

var name:string = "CJ"

}

Class Child:person {

Override Var name:string {

Willset {

}

Didset {

}

}

Override var name:string = "CJ" error

}

Column two:

Class Person2 {

var name:string = "CJ"

}

Class Child2:person2 {

Override Var name:string {

get {

Return "Chenhe"

}

set {

}

}

}

Column three:

Class Person3 {

var name:string {

Return "Chenhe"

}

Let Height:int = 12

}

Class Child3:person3 {

Override Var name:string {

Willset {

//

//        }

Didset {

//

//        }

//    }

Override Let Height:int {

Willset {

//

//        }

Didset {

//

//        }

//    }

}

Column four:

Class Person4 {

var name:string {

Return "Chenhe"

}

}

Class Child4:person4 {

Override Var name:string {

get {

Return "Chenhe"

}

set {

}

}

}

Column Five:

Class Person5 {

var name:string {

Return "Chenhe"

}

Func x () {

Print ("Hello")

}

}

Class Child5:person5 {

Override Func X () {

Print ("Good for You")

}

}

Run-time polymorphism

Let a:person5 = Child5 ()

A.x ()

Initialize dry two things, allocate space, assign values to members

The initialization method of structure body

struct Point {

var x:int

var y:int

}

Let p = Point violates the principle of initialization and does not assign a value to a member. One of the following can be listed:

Let p = Point (X:1, Y:2)

struct Point2 {

var x:int = 4

var y:int = 3

}

Let P2 = Point2 ()//This will not give an error, allocate space and assign values to the member

struct POINT3 {

var x:int

var y:int

Write a full constructor to initialize all the members

Init (xx:int,yy:int) {

x = XX

y = yy

}

}

Swift's inheritance and initialization of the struct body