public class 子類 extends 父類 {
}

class Computer3 { // 父類：電腦
    String sayHello() { // 方法：打招呼
        return "歡迎使用";
    }
}

public class Pad3 extends Computer3 { // 子類：平板電腦
    String sayHello() { // 子類重寫父類方法
        return super.sayHello() + "iPad"; // 調用父類方法并添加字符串
    }

    public static void main(String[] args) {
        Computer3 pc = new Computer3(); // 創建父類-電腦類對象
        System.out.println(pc.sayHello());

        Pad3 ipad = new Pad3(); // 創建子類-平板電腦類對象
        System.out.println(ipad.sayHello());
    }
}

public class Hello {
    public String getStr(){
        return (getClass().getName());
    }
    
    @Override 
    public String toString(){
        return (getClass().getName()+"。");
    }



    public static void main(String[] args) {
        Hello ho = new Hello();

        System.out.println("ho.getStr()："+ho.getStr());

        System.out.println("ho.toString()："+ho.toString());

    }
}

        /*ho.getStr()：Hello
        ho.toString()：Hello。*/

class Animal {
    String branch;

    public Animal(String branch) {
        this.branch = branch;
    }

    public String getBranch() {
        return branch;
    }

    public void setBranch(String branch) {
        this.branch = branch;
    }

    @Override
    public boolean equals(Object obj) {
        Animal animal = (Animal) obj;
        if (this.getBranch().equals(animal.getBranch())) {
            return true;
        } else {
            //System.out.println(this.getBranch()); ——→ 輸出“豬科”
            //System.out.println(animal.getBranch()); ——→ 輸出“犬科”
            return false;
        }
    }
}

class NewDog extends Animal {
    public NewDog(String branch) {
        super(branch);
    }
}

class NewPig extends Animal {
    public NewPig(String branch) {
        super(branch);
    }
}

public class RightResult {
    public static void main(String[] args) {
        NewPig pig = new NewPig("豬科");
        NewDog dog = new NewDog("犬科");
        if (pig.equals(dog)) {
            System.out.println("豬和狗是同類！！！");
        } else {
            System.out.println("豬和狗不是同類。");
        }
    }
}