测试一、编写九九乘法表

效果如下：

    1 x 1 = 1  
    1 x 2 = 2  2 x 2 = 4  
    1 x 3 = 3  2 x 3 = 6   3 x 3 = 9  
    1 x 4 = 4  2 x 4 = 8   3 x 4 = 12  4 x 4 = 16  
    1 x 5 = 5  2 x 5 = 10  3 x 5 = 15  4 x 5 = 20  5 x 5 = 25  
    1 x 6 = 6  2 x 6 = 12  3 x 6 = 18  4 x 6 = 24  5 x 6 = 30  6 x 6 = 36  
    1 x 7 = 7  2 x 7 = 14  3 x 7 = 21  4 x 7 = 28  5 x 7 = 35  6 x 7 = 42  7 x 7 = 49  
    1 x 8 = 8  2 x 8 = 16  3 x 8 = 24  4 x 8 = 32  5 x 8 = 40  6 x 8 = 48  7 x 8 = 56  8 x 8 = 64  
    1 x 9 = 9  2 x 9 = 18  3 x 9 = 27  4 x 9 = 36  5 x 9 = 45  6 x 9 = 54  7 x 9 = 63  8 x 9 = 72  9 x 9 = 81

Kotlin

// 打印乘法口诀
private fun printMultiplication() {
    println("编写一个程序 打印出99乘法表")
    for (i in 1..9) {
        for (j in 1..i){
            print("$j * $i = ${i*j}\t")
        }
        println()
    }
}

Swift

    /// 打印乘法口诀
    private func printMultiplication()  {
        print("编写一个程序 打印出99乘法表")
        for i in 1...9 {
            for j in 1...i {
                print("\(j) * \(i) = \(i*j) \t",terminator: "")
            }
            print("")
        }
    }

测试二、 打印1000以内质数

Kotlin

// 输出1000以内的质数
private fun printPrimes() {
    println("打印出 1000 以内的素数")
     for (n in 2..1000) {
          for (m in 2 until n) {
            if (n % m == 0) {
                break
            }
            if (n == m+1) {
                println(n)
            }
        }
    }
}

Swift

    /// 输出1000以内的质数
    private func printPrimes() {
        print("打印出 1000 以内的素数")
        for n in 2...1000 {
            for m in 2 ... n {
                if (n % m == 0) {
                    break
                }
                if (n == m + 1) {
                    print(n)
                }
            }
        }
    }

测试三、为数组编写扩展方法，实现求和的功能，指定泛型为Int数据类型

Kotlin

// 扩展Array的求和方法
fun Array<Int>.sum():Int {
    var sum = 0
    this.forEach {
        sum += it
    }
    return sum
}

// 实现一个泛型的公用方法
fun <T>Array<T>.sum() {
    for (item in this)
        println(item)
}

Swift

/// 当Array内的类型为整数时添加计算属性sum
extension Array where Element == Int {
    var sum : Int {
        var result  = 0
        self.forEach { (item) in
            result += item
        }
        return result
    }
}

测试四、Swift 协议、枚举、继承练习

• 枚举设置关联值

/// 编写一个枚举AnimalMoveType,其中走路关联脚的数量，飞翔关联翅膀数量
enum AnimalMoveType {
    case walk(foot:Int)
    case swim
    case fly(wings:Int)
}

• 自定义协议

/// 编写 Animal 协议 协议中 规定一个函数func liveAt() -> String
protocol Animal {
    var moveType: AnimalMoveType{get}
    func liveAt() -> String
}

• 协议添加默认实现

/// 为Animal 协议添加默认实现，liveAt 默认返回"earth"
extension Animal {
    func liveAt() -> String{
        return "all the annimal live at earth"
    }
}

• 编写类实现协议

class Dog: Animal {
    var moveType: AnimalMoveType
    init() {
        moveType = .walk(foot:4)
        print("this is dog")
    }
    func liveAt() -> String {
        return "Dog liveAt house"
    }
  
}

• 继承与方法重写

class Corgi: Dog {
    override func liveAt() -> String {
        return "Corgi liveAt yard"
    }
}