Swift3.0基础语法学习<二>

对象和类：

 //
 //  ViewController2.swift
 //  SwiftBasicDemo
 //
 //  Created by 思 彭 on 16/11/15.
 //  Copyright © 2016年 思 彭. All rights reserved.
 //

 import UIKit

 class ViewController2: UIViewController {

     override func viewDidLoad() {
         super.viewDidLoad()
         self.title = "基本语法《二》"

         // 1.对象和类
         var shape = Shape()
         shape.numberOfSides =
         var shapeDescription = shape.simpleDescription()
         print(shapeDescription)

         // 2.初始化创建类，init创建
         var nameShape = NameShape(name: "Sisi")
         print(nameShape.name)

         // 3.子类，继承关系
         let test = Square(sidelength: 5.0, name: "HaHa")
         print("area = \(test.area())")
         print(test.simpleDescription())

         // 4. set方法
         var traig = TriangleAndSquare(size: , name: "xixix")
         print(traig.size)
         print(traig.triangle)
     }
 }

 // 定义类
 class Shape {

     var numberOfSides =
     func simpleDescription() -> String {

         return "A shape with \(numberOfSides) sides."
     }
 }

 // 带初始化方法的类
 class NameShape {

     var numberOfSides: Int =
     var name: String
     init(name: String) {
         self.name = name
     }

     func simpleDescription() -> String {

         return "A shape with \(numberOfSides) sides."
     }
 }

 // 继承父类的子类
 class Square: NameShape {

     var sideLength: Double

     init(sidelength: Double, name: String) {
         self.sideLength = sidelength
         super.init(name: name)
         numberOfSides =
     }

     func area() -> Double {

         return sideLength * sideLength
     }
     // 重写父类方法
     override func simpleDescription() -> String {

         return "A square with sides of length \(sideLength)."
     }
 }

 // set方法
 class TriangleAndSquare {

     var size: Double = 0.0
     var triangle: Square {

         willSet {

             print(triangle.simpleDescription())
         }
     }
     init(size: Double, name: String) {
         triangle = Square(sidelength: size, name: name)
         self.size = size
     }
 }