(实验)Swift 值和引用

元组

import Foundation
var a1:(key:String,value:String) = ("name","anson")
var b1 = a1
a1.value = "tom"
print(a1)
print(b1)

输出

(key: "name", value: "tom")
(key: "name", value: "anson")

可见元组赋值是值类型传递

结构体

struct Student {

    var name:String
    var age:Int
}

var anson = Student(name: "Anson", age: 18)
anson.age = 18
var tom = anson
tom.name = "Tom"

print("\(anson.name) + \(anson.age)" )
print("\(tom.name) + \(tom.age)" )

输出

Anson + 18
Tom + 18

结构体赋值是值类型传递

类

class Teacher {
    var name:String = ""
    var age:Int = 0
}

var zhang = Teacher()
zhang.name = "zhang"
zhang.age = 64
var wang = zhang
wang.name = "wang"
print("\(zhang.name) + \(zhang.age)" )
print("\(wang.name) + \(wang.age)" )

数组

var nameList:[String] = ["anson","tom","sam"]
var secondList = nameList;
secondList.remove(at: 0)
print(nameList)
print(secondList)

输出

["anson", "tom", "sam"]
["tom", "sam"]

可见数组赋值是值类型传递
其实数组的定义就是结构体

字典

var nameDic = ["first":"anson","second":"sam"]
var secondDic = nameDic;
secondDic["first"] = "tom"
print(nameDic)
print(secondDic)

输出

["second": "sam", "first": "anson"]
["second": "sam", "first": "tom"]

可见字典赋值是值类型传递
其实字典的定义就是结构体