• 定义与实例化

class aClass {

}
struct AStructure {

}
var aStru = AStructure()
var aClas = aClass()

• 属性(与OC相同,使用.可以对类属性进行getter和setter)

class aClass {
    var name:String?
}
var aClas = aClass()
aClas.name = "class"
if aClas.name != nil {
    print("the name of aClas is \(aClas.name!)")
}

• 便利构造器(结构体自带,而类没有)

struct AStructure {
    var number = 0
    var grade = 0
}
var aStru = AStructure(number: 10, grade: 5)
print("this stu is in grade \(aStru.grade) and his/her number is \(aStru.number)")

• 类属于引用类型
  • 引用类型:Class,闭包属于引用类型,当我们使用引用类型赋值时,引用的是实例本身,而不是副本,也就是我们对新的实例操作,也会影响引用的实例

  class aClass {
      var name:String?
  }
  var aClas = aClass()
  aClas.name = "aclass"
  var bClas = aClas
  bClas.name = "bclass"
  if aClas.name != nil {
      print("the name of aClas is \(aClas.name!)")
  }
  

• 结构体属于值类型
  • 值类型:String,Int,Float等Swift基本数据类型为值类型,当每次我们使用值类型赋值时,会生成一个拷贝副本,两者之间完全不相干

  struct AStructure {
      var number = 0
      var grade = 0
  }
  var aStru = AStructure(number: 10, grade: 5)
  var bStru = aStru
  bStru.grade = 6
  print("the a grade \(aStru.grade),the b grade \(bStru.grade)")