swift 类和结构体

class Student: NSObject {
    var name = ""
    var age = 0
}

struct Teacher {
    var name = ""
    var age = 0
}

let student = Student()
let teacher = Teacher()

let ter = Teacher(name: "teacher", age: 30)

student.name = "student"
teacher.name = "teacher"
print(student.name)
print(teacher.name)

struct Teacher {
    var name = ""
    var age = 0
}

let ter = Teacher(name: "teacher", age: 30)

//因为Teacher是一个结构体，所以ter1的值其实是ter的一个拷贝副本，而不是ter本身。尽管ter和ter1有着相同的name和age，但其实它们是两个完全不同的实例
var ter1 = ter

ter1.name = "good teacher"

//通过log证明ter和ter1其中任何一个修改都不会影响另一个
print(ter.name)    //teacher
print(ter1.name)  //good teacher

class Student: NSObject {
    var name = ""
    var age = 0
}

let stu = Student()
stu.name = "good student"

//因为类是引用类型，所以stu1和stu实际上引用的是相同的Student实例
let stu1 = stu

stu1.name = "bad student"

print(stu.name)    //bad student
print(stu1.name)  //bad student

    if stu === stu1 {
          print("same Student instance")
    }