JAVA的类

类与调用

public class initCal {
    private int num1;
    private int num2;
    private char option;

    public void harvest(int n1, int n2, char o) {
        num1 = n1;
        num2 = n2;
        if (o == '+' || o == '-' || o == '*' || o == '/') {
            option = o;
        }
    }
    public void cal() {
        switch (option) {
        case '+':
            System.out.println(num1 + num2);
            break;
        case '-':
            System.out.println(num1 - num2);
            break;
        case '*':
            System.out.println(num1 * num2);
            break;
        case '/':
            System.out.println(num1 / num2);
            break;
        default:
            break;
        }
    }
}

public class cpu {

    public static void main(String[] args) {
        initCal c = new initCal();
        c.harvest(1, 2, '+');
        c.cal();
    }
}

构造函数

class baby {
    int num1;
    String str1;

    //构造代码块在创建对象的时候就会执行 创建一次，执行一次
    {
        System.out.println("构造代码块执行了");
    }

    public baby(int n1, String s1) {
        this.num1 = n1;
        this.str1 = s1;
    }

    public static void main(String[] args) {
        baby ba = new baby(1, "hello");
        baby ba2 = new baby(1, "hello");
    }
}

抽象类  继承

Animal类

abstract class Animal {
    String name;
    String color;

    public Animal(String name,String color) {
        this.name=name;
        this.color;
    }

    public void eat() {
        System.out.print("吃东西");
    }
    
    public abstract void run();
}

Dog类

public class Dog extends Animal {

    public Dog(String name, String color) {
        super(name, color);
    }

    public void run() {
        System.out.print(color + name + "四条腿跑");
    }

    public static void main(String[] args) {
        Dog dg = new Dog("海狗", "黄色");
        dg.run();
    }

}

Fish类

public class fish extends Animal {

    public fish(String name, String color) {
        super(name, color);
        // TODO Auto-generated constructor stub
    }

    public void run() {
        System.out.print(color + name + "游的快");
    }

    public static void main(String[] args) {
        fish fh = new fish("小鱼", "红色");
        fh.run();
    }

}