swift基本知识点的源码

//        print("hello world");

//        let explictFloat : Float = 4;
//        print(explictFloat)

//        let label = "My age is ";
//        let age = 18;
//        let labelAge = label + String(age);
//        print(labelAge);

//        let apples = 3;
//        let oranges = 5;
//        let appleSummary = "I have \(apples) apples\n";
//        print(appleSummary);
//        let fruitSummary = "I have \(apples + oranges) pieces of fruit";
//         print(fruitSummary);

//        let abc = 38.8;
//        let label = "My number is \(abc)";
//        print(label);

//        var shoppingList = ["apple","orange","banana","milk"];   //数组
//        print(shoppingList[1]);

//        var peopleSex = ["Jack" : "I'm a boy","Lisa" : "I'm a girl"];  //字典
//        print(peopleSex["Jack"]);

//        let individualScores = [75,43,103,87,12];    //if else 进行判断
//        var teamScore = 0;
//        for score in individualScores {
//
//            if score > 50 {
//                teamScore += 3;
//            } else {
//                teamScore += 1;
//            }
//
//        }
//
//        print(teamScore);

//        var optionalName: String? = "Jack";        //用问号来标记某个变量的值是可选的
//        optionalName = nil;
//        var greeting = "Hello!";
//        if let name = optionalName {
//        greeting = greeting + String(name);
//            print(greeting);
//
//        }else{
//            greeting = greeting + String(optionalName);//+ "Lisa";
//            print(greeting);
//        }

//        let vegetable = "red pepper";               //switch 的使用
//
//        switch vegetable {
//        case "celery":
//            let vegetableComment = "Hi I'm will go home";
//            print(vegetableComment);
//            case "cucumber","watercress":
//            let vegetableComment = "I'm lisa,come here";
//            print(vegetableComment);
//        case let x where x.hasSuffix("pepper"):
//            let vegetableComment = "Is it a spicy \(x)?";
//            print(vegetableComment);
//        default:
//            let vegetableComment = "EveryThing is taste good in a soup";
//            print(vegetableComment);
//        }
//

//        let interestingNumbers = [                     //for-in  实现字典的遍历
//            "Prime" : [2, 3, 5, 7, 11, 13],
//            "Fibonacci" : [1, 1, 2, 3, 5, 8],
//            "Square" : [1, 4, 9, 16, 25],
//        ]
//
//        var largest = 0;
//
//        for (kind, numbers) in interestingNumbers {
//
//            for number in numbers {
//                if number > largest {
//                    largest = number;
//                }
//            }
//            print(largest);
////            print(kind,largest);
//        }

//
//        var n = 2;        //while实现循环
//        while n < 100 {
//            n = n*2;
//        }
//
//        print(n);

//
//        var m = 2;         //repeat-while 实现循环
//
//        repeat {
//            m = m*2;
//        }while m < 100
//
//        print(m);

//        //使用 for 循环
//        var firstForLoop = 0;
//
//        for var i = 0;i < 3;++i {
//
//            firstForLoop += i;
//        }
//
//        print(firstForLoop);

//        //函数和闭包
//        func greet(name: String, day: String) ->String{
//
//            return "Hello \(name), Today is \(day).";
//        }
//
//        print(greet("Jack", day: "Tuesday"));

//        func getGasPrice() ->(Double,Double,Double){     //使用一个元组来返回多个值。
//
//            return (3.59, 3.69, 3.79);
//        }
//
//
//        print(getGasPrice());

//        //函数的参数是可变的，用一个数组来获取它们
//
//        func sumOf(numbers: Int...) ->Int{
//
//            var sum = 0;
//            for number in numbers {
//
//                sum += number;
//            }
//            print(sum);
//            return sum;
//        }
//
////        sumOf();
//        sumOf(42, 597, 12);

class nameShape {

var numberOfsides: Int = 0;
var name: String;

init(name: String){
self.name = name;
}

func simpleDescription() ->String{
return "A shape with \(numberOfsides) sides.";
}
}

class Square:nameShape{

var sideLength: Double;
init(sideLength: Double, name: String){

self.sideLength = sideLength;
super.init(name: name);

numberOfsides = 4;
}

func area() ->Double {

return sideLength * sideLength;

}

override func simpleDescription() -> String {

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

}

}

//        let test = Square(sideLength: 5.5, name: "Lili");
//
//        let area = test.area();
//        print(area);
//
//        let description = test.simpleDescription();
//        print(description);

//        class Circle:nameShape {    //圆的类定义
//            var radius: Double;
//            init(radius: Double,name: String){
//                self.radius = radius;
//                super.init(name: name);
//            }
//
//            func area() ->Double{
//
//                return M_PI * radius * radius;
//
//            }
//
//            override func simpleDescription() -> String {
//
//                return "A Cicle with radius of  \(radius)";
//            }
//        }
//
//        let test = Circle(radius: 4.8, name: "myCircle");
//
//        print(test.name);
//
//        let area = test.area();
//        print(area);
//
//        let description = test.simpleDescription();
//        print(description);
//
//

class EquilateralTriangle: nameShape{

var sideLength: Double = 0.0;

init(sideLength: Double,name: String){

self.sideLength = sideLength;
super.init(name: name);
numberOfsides = 3;
}

func area() -> Double {

return sideLength * sideLength;
}

var perimeter: Double{     //属性可以有 getter 和 setter 。

get {
return 3.0 * sideLength;
}

set {
sideLength = newValue/3.0;    //在 perimeter 的 setter 中,新值的名字是 newValue。你可以在 set 之后显示的设置一个名 字。
}
}

override func simpleDescription() -> String {

return "An equilateral triangle with sides of length \(sideLength)";
}

}

//        let triangle = EquilateralTriangle(sideLength: 5, name: "my Triangle");
//
//        print(triangle.perimeter);
//
//        triangle.perimeter = 9.9;
//
//        print(triangle.sideLength);
//
//        let description = triangle.simpleDescription();
//
//        print(description);

//如果你不需要计算属性但是需要在设置一个新值之前运行一些代码,使用willSet和didSet。 比如,下面的类确保三角形的边长总是和正方形的边长相同。

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);

}

}

let triangleAndSquare = TriangleAndSquare(size: 10, name: "another test shape");
print(triangleAndSquare.square.sideLength);
print(triangleAndSquare.triangle.sideLength);
triangleAndSquare.square = Square(sideLength: 50, name: "larger Square");

print(triangleAndSquare.triangle.sideLength);