swift的语法小demo2

 

//
//  main.swift
//  SwiftGrammarStudy
//
//  Created by dongway on 14-6-6.
//  Copyright (c) 2014年 dongway. All rights reserved.
//

import Foundation
//父类
class NamedShape{
    var numberOfSides:Int = 0
    var name:String
    
    init(name:String){
        println("1:\(name)")
        self.name = name
    }
    
    func simpleDescription() -> String{
        var simpleDescription:String = "1:A shape width \(numberOfSides) sides"
        println(simpleDescription)
        return simpleDescription
    }
}

var shape = NamedShape(name:"Martin")
shape.numberOfSides = 7
var shapeDescription = shape.simpleDescription()

//子类
class Square:NamedShape{
    var sideLength:Double
    init(sideLength:Double,name: String) {
        self.sideLength = sideLength
        super.init(name:name)
        numberOfSides = 4
        println("2:\(sideLength)  \(name)  \(numberOfSides)")
    }
    
    func area() -> Double{
        var area = sideLength*sideLength
        println("2:area:\(area)")
        return area
    }
    
    override func simpleDescription() -> String{
        var desc:String = "A shape width \(sideLength) sides"
        println("2:simpleDescription:\(desc)")
        return desc
    }
    
}

let test = Square(sideLength:5.0,name:"Martin")
test.area()
test.simpleDescription()


class EquilateralTriangle: NamedShape {
    var sideLength: Double = 0.0
    
    init(sideLength: Double, name: String) {
        self.sideLength = sideLength
        super.init(name: name)
        numberOfSides = 3
    }
    
    var perimeter: Double {
        get {
            return sideLength
        }
        set {
            println(newValue)
            sideLength = newValue//这里的newValue应该是个保留字，表示传入的参数值
        }
    }
    
    override func simpleDescription() -> String {
        return "An equilateral triangle with sides of length \(sideLength)."
    }
}

var triangle = EquilateralTriangle(sideLength: 3.1, name: "a triangle")
triangle.perimeter = 9.9 //9.9传给了newValue
println("\(triangle.perimeter)  \(triangle.sideLength)")


class TriangleAndSquare {
    var triangle: EquilateralTriangle {
    willSet {
        square.sideLength = newValue.sideLength
    }
    }
    
    var square: Square {
    willSet {
        triangle.sideLength = newValue.sideLength
    }
    }
    
    init(size: Double, name: String) {
        square = Square(sideLength: size, name: name)
        triangle = EquilateralTriangle(sideLength: size, name: name)
    }
}
var triangleAndSquare = TriangleAndSquare(size: 10, name: "another test shape")
println("3:\(triangleAndSquare.square.sideLength)")
println("3:\(triangleAndSquare.triangle.sideLength)")
triangleAndSquare.square = Square(sideLength: 50, name: "larger square")
println("3:\(triangleAndSquare.square.sideLength)")
println("3:\(triangleAndSquare.triangle.sideLength)")

/*
    类方法跟函数的重要区别
    1，类方法调用时，第一个参数名必须省略
    2，类方法可以指定两个指向同一属性的两个参数名，调用类方法时使用第一个参数名，在方法内部使用第二个参数名（不明所以）
*/
class Counter {
    var count: Int = 0
    func incrementBy(amount: Int, numberOfTimes times: Int) {
        count += amount * times
    }
    
    func increment(amount:Int,times:Int){
        println("4:\(times)")
    }
}
var counter = Counter()
counter.incrementBy(2, numberOfTimes: 7)
println("4:\(counter.count)")
counter.increment(1,times:2)