Swift 定义枚举类

//定义一个简单的枚举类
enum  Skin{
  case White
  case Black
  case Yellow
}

//定义一个student类
class Student{
  var name = "张三"
  var age = 26   
  var skin:Skin = .Yellow
}

//可以在其他类实例化对象
let student = Student()
print(student.name)
print(student.age)
print(student.skin)
//打印结果为 张三 26 yellow

添加构造器

enum  Skin{
  case White
  case Black
  case Yellow
}
//定义一个student类
class Student{
  var name = "张三"
  var age = 26   
  var skin:Skin = .Yellow

  //使用self来区分是否是全局的变量
   init(name:String,age:Int,skin:Skin) {
        self.name = name
        self.age = age
        self.skin = skin
    }
}

//实力化
let student = Student(name: "小米", age: 26, skin: .White)
print(student.name)
print(student.age)
print(student.skin)
//打印结果为 小米 26 white

便利构造器

enum Skin{
    case Black
    case White
    case Yellow
}

class Student{
    var name = "张三"
    var age = 26
    var skin:Skin = .Yellow
    
    init(name:String,age:Int,skin:Skin) {
        self.name = name
        self.age = age
        self.skin = skin
    }
//
    //便利构造器
    convenience init(age:Int) {
      self.init(name: "小米", age: age, skin: .White)
    }
}
// 初始化的时候会有两种选择 一种是构造器中的三个参数全部更改，一种是构造器中只改变年龄
let student = Student(age:100)
print(student.name)
print(student.age)
print(student.skin)
//打印结果为 小米 100 white