Swift struct struct

Objective

• A struct is a value type and is assigned only if it is given a variable or constant, or is called by a function.

1, the creation of the structure body

• Structure BASIC structure

  struct 结构体名 {    var 或 let 字段名 = 初始化值    var 或 let 字段名: 类型}

  struct Student {    var age = 0}var stu = Student()/// struct      结构体关键字/// Student     结构体名称/// student()   创建一个结构体变量

1.1 Standard Definition

• Definition of the structure body

  • When you define a struct field, you can define a field name directly and assign an initial value to the field name. Or simply define a field name, do not assign an initial value, but a field that does not assign an initial value must be assigned an initial value when creating a struct variable.

    struct Student {                                  var name: String                           // 只定义一个字段名，不赋初始值    var age = 0                                // 定义一个字段名，并且给字段名赋初始值}

• Use of the structure body

  • When you create a struct variable, the fields of the struct must all have an initial value, or an error will be made.

    let s = Student(name: "appple", age: 8)        // 创建结构体变量时初始化结构体的字段print("\(s.name), \(s.age)")                   // 结构体类型变量值的调用

1.2 Basic Definitions

• Definition of the structure body

  • Each field name is assigned an initial value.

    struct BookInfo {                                   var ID: Int = 0                            // 每个字段名都赋初始值    var Name: String = "Default"    var Author: String = "Default"    var RootType: String = "Default"}

• Use of the structure body

  • When you create a struct variable, the fields of the struct must all have an initial value, or an error will be made.

    let book = BookInfo()                          // 创建结构体变量时不再需要初始化结构体的字段print("\(book.ID), \(book.Name), \(book.Author), \(book.RootType)")     // 结构体类型变量值的调用

Swift struct struct