Java-集合编程小练习

Posted 2020-11-21 HJ0101

需求:

代码:

/**
 * 
 * 汽车类
 *
 */
public class Car {
    private String brand;//汽车品牌
    private double price;//汽车价格
    private String color;//汽车颜色
    public Car() {
        
    }
    
    public Car(String brand, double price, String color) {
        this.setBrand(brand);
        this.setPrice(price);
        this.setColor(color);
    }
    public String getBrand() {
        return brand;
    }
    public void setBrand(String brand) {
        this.brand = brand;
    }
    public double getPrice() {
        return price;
    }
    public void setPrice(double price) {
        this.price = price;
    }
    public String getColor() {
        return color;
    }
    public void setColor(String color) {
        this.color = color;
    }
    @Override
    public String toString() {
        return "品牌:" + brand + "\\n价格:" + (int)price + "\\n颜色:" + color+"\\n";
        
    }

    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + ((brand == null) ? 0 : brand.hashCode());
        result = prime * result + ((color == null) ? 0 : color.hashCode());
        long temp;
        temp = Double.doubleToLongBits(price);
        result = prime * result + (int) (temp ^ (temp >>> 32));
        return result;
    }

    @Override
    public boolean equals(Object obj) {
         if(this.getBrand().equals(brand)&&this.getPrice() == price&&this.getColor().equals(color)) {
            return true;
         }else
             return false;
    }
    
    
}

 

/**
 * 汽车管理类
 */
import java.util.HashSet;
import java.util.Iterator;
import java.util.Scanner;
import java.util.Set;

public class CarManager {
    HashSet<Car> set = new HashSet<>();
    Scanner sc = new Scanner(System.in);

    // 添加汽车的方法:
    public void add() {
        Car car = new Car();
        System.out.println("请输入汽车的品牌:");
        car.setBrand(sc.next());
        System.out.println("请输入汽车的价格:");
        car.setPrice(sc.nextDouble());
        System.out.println("请输入汽车的颜色:");
        car.setColor(sc.next());
        set.add(car);
        System.out.println("汽车信息添加成功!!");
    }
    // 查看所有汽车的信息
    public void show() {
        if(set.isEmpty()) {
            System.out.println("还没有汽车信息,快添加一些吧!");
        }else {
            System.out.println("汽车信息:");
            for(Car car:set)
            {
                System.out.println(car);
            }
        }
        
    }
    //根据汽车品牌修改汽车信息
    public void changBrand(){
        boolean flag = false;
        System.out.println("请输入您要修改的汽车品牌:");
        Scanner sc = new Scanner(System.in);
        String brand = sc.next();
        System.out.println("请输入您要修改的价格:");
        Double price = sc.nextDouble();
        Iterator<Car> it = set.iterator();
        while(it.hasNext()) {
            Car c = it.next();
            if(c.getBrand().equals(brand)) {
                c.setPrice(price);
                flag = true;
            }
        }
        if(flag) {
            System.out.println("修改成功!!");
        }else
            System.out.println("没有找到该品牌的汽车~");
    }
    //根据汽车品牌删除汽车的方法
    public void remove() {
        boolean flag = false;
        System.out.println("请输入您要删除的汽车品牌:");
        Scanner sc = new Scanner(System.in);
        String brand = sc.next();
        Set<Car> set1 = new HashSet<Car>();
        for(Car car:set) {
            if(car.getBrand().equals(brand)) {
                set1.add(car);
                flag = true;
            }
        }
        if(flag) {
            set.removeAll(set1);
            System.out.println("删除成功!!");
        }else
            System.out.println("没有找到该品牌的汽车~");
    }
}

/**
 * 测试类(程序启动类)
 */
import java.util.Scanner;

public class CarTest {
    //菜单方法
    public void menu() {
        System.out.println("**************************");
        System.out.println("\\t1.添加汽车信息");
        System.out.println("\\t2.查看所有汽车信息");
        System.out.println("\\t3.根据汽车品牌修改汽车价格");
        System.out.println("\\t4.根据汽车品牌删除汽车");
        System.out.println("\\t0.退出程序");
        System.out.println("**************************");
        System.out.println("请输入您选择的操作:");
    }
    public static void main(String[] args) {
        CarManager cm = new CarManager();
        CarTest ct = new CarTest();
        ct.menu();
        Scanner sc = new Scanner(System.in);
        
        while(true) {
            int n = sc.nextInt();
            switch(n) {
            case 1:
                cm.add();
                ct.menu();
                continue;
            case 2:
                cm.show();
                ct.menu();
                continue;
            case 3:
                cm.changBrand();
                ct.menu();
                continue;
            case 4:
                cm.remove();
                ct.menu();
                continue;
            case 0:
                System.exit(1);
            default:
                System.out.println("选择错误,请重新选择:");
            }
        }
    }
}