function、structures、classes-优快云博客

本文链接：https://blog.youkuaiyun.com/JUST_lOVE_LE/article/details/110246265

本文介绍了Swift语言的基本概念，包括函数定义及调用、结构体与类的使用方法，并通过具体示例展示了如何创建结构体实例及类的继承特性。

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函数定义:

//定义无参函数
func sayRan() {
    print("Ran!");
}
//调用
sayRan()
//定义有参函数带返回值
func calcMidpoint(firstNum: Int, secondNum: Int) -> Int {
    let result = (firstNum + secondNum) / 2;
    return(result);
}
//调用
let resultA = calcMidpoint(firstNum: 10, secondNum: 15);
let resultB = calcMidpoint(firstNum: 34, secondNum: 8);

print(resultA);
print(resultB);

定义结构体

struct Person {
    var name: String;
    var age: Int;
    var location: String;
    
    func whoAmI() {
        print("Hi, I'm \(name)! I'm \(age) and live in \(location).");
    }
}
//实例化
let aPerson = Person(name: "David", age: 22, location: "Australia");
aPerson.whoAmI();

struct WaterMeter {
    var litresUsed: Int = 0;
    var customer: Person = Person(name: "Jane", age: 66, location: "Australia");
}
let theMeter = WaterMeter();
print(theMeter.customer.name);
print(theMeter.litresUsed);

类


class Animal {
    var animalName: String;
    var numberOfLimbs: Int;
    
    func makeNoise() {
        // Do Nothing!
    }
    
    init(animalName: String, numberOfLimbs: Int) {
        self.animalName = animalName;
        self.numberOfLimbs = numberOfLimbs;
    }
}



class Cat:Animal {
    var breed: String = "";
    
    override func makeNoise() {
        print("Meow!")
    }
    
    init(animalName: String, numberOfLimbs: Int, breed: String) {
        self.breed = breed;
        super.init(animalName: animalName, numberOfLimbs: numberOfLimbs);
    }
}

let myCat = Cat(animalName: "Whiskers", numberOfLimbs: 4, breed: "Ragdoll");
print(myCat.numberOfLimbs);
print(myCat.breed);
myCat.makeNoise();