Java day7

                数据类型

        基本数据类型        (四类八中) : 变量只能指向常量池

        byte        

        short

        int 

        long

        float

        double       

        char

        boolean

        引用数据类型的变量(指针,引用)  (类 , 数组  两大类) 

       数组

         int[] 

        byte[]

       类

        Goods

        Dog

        既可以指向常量池又可指向堆

        Byte        

        Short

        Int 

        Long

        Float

        Double       

        Character

        Boolean

        String

String的底层是什么
        JDK 1.8之前是char[]

        JDK 1.9之后是byte[]

String类的成员变量

        char[] value

String 类 常用的方法
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版权声明：本文为CSDN博主「葫芦娃奇袭塞伯坦」的原创文章，遵循CC 4.0 BY-SA版权协议，转载请附上原文出处链接及本声明。
原文链接：https://blog.csdn.net/qq_61933330/article/details/125495473

package 汽车出租系统;

public class Car {
    private String brand;
    private String model;
    private String color;
    private String leaser;
    private Double rent;
    private Integer day;
    private Integer state;

    public void show(){
        System.out.print("汽车品牌:" + this.brand + "   ");
        System.out.print("汽车型号:" + this.model + "   ");
        System.out.print("汽车颜色:" + this.color + "   ");
        System.out.print("租车人:" + this.leaser + "   ");
        System.out.print("日租金:" + this.rent + "   ");
        System.out.print("租借天数:" + this.day + "   ");
        System.out.print("状态:" + (this.state == 0 ? "未租借" : "以租借")  + "   ");
        System.out.println();
        System.out.println("--------------------------------------------------------------------------------------------------");
    }

    public String getBrand() {
        return brand;
    }

    public void setBrand(String brand) {
        this.brand = brand;
    }

    public String getModel() {
        return model;
    }

    public void setModel(String model) {
        this.model = model;
    }

    public String getColor() {
        return color;
    }

    public void setColor(String color) {
        this.color = color;
    }

    public String getLeaser() {
        return leaser;
    }

    public void setLeaser(String leaser) {
        this.leaser = leaser;
    }

    public Double getRent() {
        return rent;
    }

    public void setRent(Double rent) {
        this.rent = rent;
    }

    public Integer getDay() {
        return day;
    }

    public void setDay(Integer day) {
        this.day = day;
    }

    public Integer getState() {
        return state;
    }

    public void setState(Integer state) {
        this.state = state;
    }
}

package 汽车出租系统;

import java.util.Scanner;

public class Demo {

    static Scanner sc = new Scanner(System.in);

    static Car[] cars = new Car[10];

    //静态代码块,储存默认数据
    static {
        Car car0 = new Car();
        car0.setBrand("奥迪");
        car0.setModel("A1");
        car0.setColor("黑");
        car0.setState(0);
        cars[0] = car0;

        Car car9 = new Car();
        car9.setBrand("奥迪");
        car9.setModel("A2");
        car9.setColor("黑");
        car9.setState(0);
        cars[1] = car9;

        Car car8 = new Car();
        car8.setBrand("奥迪");
        car8.setModel("A3");
        car8.setColor("黑");
        car8.setState(0);
        cars[2] = car8;

        Car car7 = new Car();
        car7.setBrand("五菱");
        car7.setModel("迷你");
        car7.setColor("白");
        car7.setState(0);
        cars[3] = car7;

        Car car6 = new Car();
        car6.setBrand("老头乐");
        car6.setModel("迷你");
        car6.setColor("红");
        car6.setState(0);
        cars[4] = car6;

    }

    //主函数
    public static void main(String[] args) {
        int a = 0;
        do {
            System.out.println("-----欢迎进入汽车租借系统-----");
            System.out.println("1.添加汽车");
            System.out.println("2.删除汽车");
            System.out.println("3.查看汽车");
            System.out.println("4.汽车出租");
            System.out.println("5.汽车归还");
            System.out.println("6.退出");
            System.out.println("请输入:");
            a = sc.nextInt();
            switch (a) {
                case 1 :
                    addCar();
                    break;
                case 2 :
                    deleteCar();
                    break;
                case 3 :
                    display();
                    break;
                case 4 :
                    rentCar();
                    break;
                case 5 :
                    giveBack();
                    break;
                case 6 :
                    System.out.println("退出!");
                    break;
                default:
                    break;
            }
        } while (true);



    }

    //添加
    public static void addCar(){
        Car car = new Car();
        System.out.println("请输入汽车品牌:");
        car.setBrand(sc.next());
        System.out.println("请输入汽车型号:");
        car.setModel(sc.next());
        System.out.println("请输入汽车颜色:");
        car.setColor(sc.next());
        System.out.println("请输入状态(以出租为1,未出租为0):");
        car.setState(sc.nextInt());
        for (int i = 0; i < cars.length; i++) {
            if (cars[i] == null){
                cars[i] = car;
                break;
            }
            if (cars.length - 1 == i){
                System.out.println("添加失败,储存空间不足,请扩容!");
                break;
            }
        }
    }

    //删除
    public static void deleteCar(){
        display();
        System.out.println("请输入删除多少号汽车:");
        int n = sc.nextInt() - 1;
        cars[n] = null;
    }

    //查看
    public static void display(){
        for (int i = 0; i < cars.length; i++) {
            System.out.println((i+1) + "号车:");
            if (cars[i] != null){
                cars[i].show();
            }else {
                System.out.println("空");
            }
        }
    }

    //租借
    public static void rentCar(){
        display();
        //请选择几号车辆
        System.out.println("请选择出租几号车辆:");
        int x = sc.nextInt() - 1;
        Car car = cars[x];
        if (car == null){
            System.out.println("该汽车不存在!请重新选择!");
        }else if(car.getState() == 1) {
            System.out.println("该汽车已出租!请重新选择!");
        }else {
            System.out.println("请输租车人:");
            car.setLeaser(sc.next());
            System.out.println("请输入日租金:");
            car.setRent(sc.nextDouble());
            System.out.println("请输入租借天数:");
            car.setDay(sc.nextInt());
            car.setState(1);
        }
    }

    //归还
    public static void giveBack(){
        display();
        //请选择几号车辆
        System.out.println("请选择归还几号车辆:");
        int x = sc.nextInt() - 1;
        Car car = cars[x];
        if (car == null){
            System.out.println("该汽车不存在!请重新选择!");
        }else if(car.getState() == 0) {
            System.out.println("该汽车未出租!请重新选择!");
        }else {
            car.setLeaser(null);
            car.setRent(null);
            car.setDay(null);
            car.setState(0);
            double a = car.getRent() * car.getDay();
            System.out.println("请支付金额:"  +a+ "元");
        }
    }
}