day09作业

一.填空题

1.方法 2.堆内存 3.构造方法 4.this 5.this 6.static 7.使用类名进行访问 8.package import class 9.关键字 10.lang

二.选择题

1.D 2.B 3.D 4.AC 5.AC

三.判断题

1.√ 2.× 3.√ 4.× 5.√ 6.× 7.√

四.

1.构造方法的作用是给对象进行初始化。

特点：1.方法名与类名相同（大小写也一致）

2.没有返回值类型，连void也没有

3.没有具体的返回值return

注意事项：

1.如果我们没有给出构造方法，系统将自动给出一个无参构造方法。

2.如果我们给出了构造方法，系统将不会提供默认的无参构造方法。

可以不写return语句。

2.setXxx()方法和构造方法

3

4.a. 随着类的加载而加载
b:优先于对象存在
c:被类的所有对象共享

d.可以通过类名调用

当对象出现共享数据时，该数据用static修饰。

5.public static void main(String[] args){}

public : 被jvm调用,所以权限要足够大
static : 被jvm调用,不需要创建对象,直接类名.调用即可
void   : 被jvm调用,不需要有任何的返回值
main   : 只有这样写才能被jvm识别,main不是关键字
String[] args : 以前是用来接收键盘录入的

class Test13_Vehicle {
    public static void main(String[] args) {
        Vehicle a = new Vehicle();
        a.setSpeed(10);
        a.setSize(10);
        System.out.println(a.speedUp() + " " + a.speedDown());
    }
}
class Vehicle {
    private int speed;
    private int size;
    public Vehicle(){}
    public Vehicle(int speed,int size){
        this.speed = speed;
        this.size = size;
    }
    public void setSpeed(int speed){
        this.speed = speed;
    }
    public int getSpeed(){
        return speed;
    }
    public void setSize(int size){
        this.size = size;
    }
    public int getSize(){
        return size;
    }
    public int speedUp(){
        return speed += 1;
    }
    public int speedDown(){
        return speed -= 1;
    }
}

class Test10_Person {
    public static void main(String[] args) {
        Person p = new Person();
        p.setName("张三");
        p.setAge(24);
        p.display();
    }
}

class Person {
    private String name;
    private int age;
    public Person(){}
    public Person(String name,int age){
        this.name = name;
        this.age = age;
    }
    public void setName(String name){
        this.name = name;
    }
    public String getName(){
        return name;
    }
    public void setAge(int age){
        this.age = age;
    }
    public int getAge(){
        return age;
    }
    public void display(){
        System.out.println("姓名：" + name + " " + "年龄：" + age);
    }
}

class Test11_Circle {
    public static void main(String[] args) {
        Circle c = new Circle(1.5);
        System.out.println(c.getArea() + " " + c.getPerimeter());
    }
}

class Circle {
    private double radius;
    public Circle(){}
    public Circle(double radius){
        this.radius = radius;
    }
    public void setRadius(double radius){
        this.radius = radius;
    }
    public double getRadius(){
        return radius;
    }
    public double getArea(){
        return 3.14 * radius * radius;
    }
    public double getPerimeter(){
        return 2 * 3.14 * radius;
    }
}

class Test12_Network {
    public static void main(String[] args) {
        Network a = new Network("Mike","123456","123456");
        System.out.println("用户ID：" + a.getId() + " " + "用户密码：" + a.getPassword() + " " + "用户邮箱：" + a.getEmail() + "@gameschool.com");
    }
}

class Network {
    private String id;
    private String password;
    private String email;
    public Network(){}
    public Network(String id,String password,String email){
        this.id = id;
        this.password = password;
        this.email = email;
    }
    public void setId(String id){
        this.id = id;
    }
    public String getId(){
        return id;
    }
    public void setPassword(String password){
        this.password = password;
    }
    public String getPassword(){
        return password;
    }
    public void setEmail(String Email){
        this.email = email;
    }
    public String getEmail(){
        return email;
    }

}

class Test14_Calculaion {
    public static void main(String[] args) {
        Calculaion n = new Calculaion(10);
        System.out.println(n.add() + " " + n.sub() + " " + n.times() + " " + n.div());
    }
}

class Calculaion {
    private int num;
    public Calculaion(){}
    public Calculaion(int num){
        this.num = num;
    }
    public void setNum(int num){
        this.num = num;
    }
    public int getNum(){
        return num;
    }
    public int add(){
        return num += 2;
    }
    public int sub(){
        return num -= 2;
    }
    public int times(){
        return num *= 2;
    }
    public int div(){
        return num /= 2;
    }
}

class Test15_Draw {
    public static void main(String[] args) {
        Draw p = new Draw(10,3);
        p.drawTrian();
        p.drawRec();
        p.drawPra();
    }
}

class Draw {
    private int count;
    private int lines;
    public Draw(){}
    public Draw(int count,int lines){
        this.count = count;
        this.lines = lines;
    }
    public void setCount(){
        this.count = count;
    }
    public int getCount(){
        return count;
    }
    public void setLines(){
        this.lines = lines;
    }
    public int getLines(){
        return lines;
    }
    public void drawTrian(){
        int m = 0;
        a:for (int i = 0;i < lines ;i++ ) {
            for (int k = 0;k < lines - i ;k++ ) {
                System.out.print(" ");
            }
            for (int j = 1;j <= 2 * i - 1 ;j++ ) {
                System.out.print("*");
                m++;
                if (m == count) {
                    break a;
                }
            }
            System.out.println();
        }
    }
    public void drawRec(){
        int row = count / lines;
        int m = 0;
        a:for (int i = 0;i < lines ;i++ ) {
            for (int j = 0;j <= row ;j++ ) {
                System.out.print("*");
                m++;
                if (m == count) {
                    break a;
                }
            }
            System.out.println();
        }
    }
    public void drawPra(){
        int row = count / lines;
        int m = 0;
        a:for (int i = 0;i < lines ;i++ ) {
            for (int j = 1;j < i ;j++ ) {
                System.out.print(" ");
            }
            for (int k = 0;k <= row;k++ ) {
                System.out.print("*");
                m++;
                if (m == count) {
                    break a;
                }
            }
            System.out.println();
        }
    }
}

class Test16_Fridge {
    public static void main(String[] args) {
        Fridge f = new Fridge();
        f.setBrand("海尔");
        f.setHorsepower("100匹");
        f.setTemperature("零下5℃");
        f.heat();
        f.refrigeration();
        f.ventilate();
    }
}

class Fridge {
    private String brand;
    private String horsepower;
    private String temperature;
    public Fridge(){}
    public Fridge(String brand,String horsepower,String temperature){
        this.brand = brand;
        this.horsepower = horsepower;
        this.temperature = temperature;
    }
    public void setBrand(String brand){
        this.brand = brand;
    }
    public String getBrand(){
        return brand;
    }
    public void setHorsepower(String horsepower){
        this.horsepower = horsepower;
    }
    public String getHorsepower(){
        return horsepower;
    }
    public void setTemperature(String temperature){
        this.temperature = temperature;
    }
    public String getTemperature(){
        return temperature;
    }
    public void heat(){
        System.out.println("加热");
    }
    public void refrigeration(){
        System.out.println("制冷");
    }
    public void ventilate(){
        System.out.println("通风");
    }
}