Object-C ---) Swift (Class 8) and struct

Object-C ---) Swift (Class 8) and struct

In Swift, classes and struct have high similarity. The main differences between the two are:
1. struct does not support inheritance
2. struct does not support definition of the destructor
3. struct is a value type, while class is a reference type.

Syntax format of the definition class:

[Modifier] class name {zero to multiple constructors zero to multiple attributes zero to multiple methods zero to multiple subscript}

For a class definition, there are three most common members: constructor, attribute, and method. If the programmer does not provide constructor for a class, the system provides a default, non-parameter constructor for this class. Once the programmer provides the constructor for the class, the system will not provide the default constructor for the class.

# Define the structure syntax format:

[Modifier] struct name {zero to multiple constructors zero to multiple attributes zero to multiple methods zero to multiple subscript}

Struct cannot define final, Because struct does not support inheritance. If the programmer does not provide a constructor for the struct, the system provides two constructor for the struct: A non-parameter constructor and a constructor that initializes all storage properties.

Syntax:

[Modifier] func method name (parameter list)-[-> return value type] {// specific function code}

If you want to define a class method, you can use the class modifier.

class Person{var name:String=""var age:Int=0func say(content:String){print(content)}   }

No constructor is defined in the Code above. The system will provide a default non-parameter constructor for it, but this default constructor will not assign an initial value to the storage attribute, therefore, programs must specify initial values for these storage attributes.
Note: The class is a reference type.

Var p: Person p = Person () p. name = "" var p1 = p p1.name = "Sun Wukong" print (p. name) // output Sun Wukong

Reference Type comparison

The reference type has two operators: = and! =, These two operators can only be used to compare the number of referenced types. When two referenced variables point to the same instance, and two referenced variables point to the same instance, = true for comparison. When two referenced variables do not point to the same instance ,! = Compare to get true

Class Person {var name: String = "" var age: Int = 0 init (name: String, age: Int) {self. name = nameself. age = age} func say (content: String) {print (content)} var p1 = Person (name: "Sun Wukong", age: 2100) var p2 = Person (name: "maid", age: 48) print (p1 = p2) // outputs falseprint (p1! = P2) Output truevar p3 = p1print (p1 = p3) // Output true

Let's talk about struct.

Struct Monkey {var name: Stringvar age: Intfunc say () {print ("\ (name) age \ (age)") }}var monkey = Monkey (name: "Sun Wukong", age: 1500) print (monkey. name)

The code above calls one of the constructors with two parameters of Monkey to create an instance. The struct creates two constructors by default: A constructor without parameters and a constructor that initializes all storage properties.
When no parameter constructor is called

Var monkey = Monkey () print (monkey. age) // output 0