day11作业

一.选择题

1.B 2.D 3.AB 4.C

二.判断题

1.× 2.√

三.简答题

1.

多态就是事物存在的多种形态。

提高程序的复用性，提高程序的可扩展性和可维护性。

2.

向上转型是指父类引用指向子类对象，向下转型是指子类引用指向父类对象。

import java.util.Scanner;

class Test5_Pizza {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        System.out.println("请选择想要制作的披萨(1.培根披萨 2.海鲜披萨)：");
        int choice = sc.nextInt();
        System.out.println("请输入培根克数：");
        int gram = sc.nextInt();
        System.out.println("请输入披萨大小：");
        int size = sc.nextInt();
        System.out.println("请输入披萨价格：");
        int price = sc.nextInt();
        if (choice == 1) {
            PeiGenPizza p1 = new PeiGenPizza(gram,size,price);
            p1.show1();
        }else if(choice == 2){
            HaiXianPizza p2 = new HaiXianPizza(gram,size,price);
            p2.show2();
        }
    }
}

class Pizza {
    private int gram;
    private int size;
    private int price;
    public Pizza(){}
    public Pizza(int gram,int size,int price){
        this.gram = gram;
        this.size = size;
        this.price = price;
    }
    public void setGram(int gram){
        this.gram = gram;
    }
    public int getGram(){
        return gram;
    }
    public void setSize(int size){
        this.size = size;
    }
    public int getSize(){
        return size;
    }
    public void setPrice(int price){
        this.price = price;
    }
    public int getPrice(){
        return price;
    }
}

class PeiGenPizza extends Pizza {
    public PeiGenPizza(){}
    public PeiGenPizza(int gram,int size,int price){
        super(gram,size,price);
    }
    public void show1(){
        System.out.println("名称：培根披萨" + "
" + "价格：" + getPrice() + "元" + "
" + "大小：" + getSize() + "寸" + "
" + "培根克数：" + getGram() + "克");
    }
}

class HaiXianPizza extends Pizza {
    public HaiXianPizza(){}
    public HaiXianPizza(int gram,int size,int price){
        super(gram,size,price);
    }
    public void show2(){
        System.out.println("名称：海鲜披萨" + "
" + "价格：" + getPrice() + "元" + "
" + "大小：" + getSize() + "寸" + "
" + "培根克数：" + getGram() + "克");
    }
}

import java.util.Scanner;

class Test6_Drink {
    public static void main(String[] args) {
        Scanner sc  = new Scanner(System.in);
        System.out.println("请选择饮料(1.咖啡 2.矿泉水 3.可乐)：");
        int choice = sc.nextInt();
        System.out.println("请输入购买容量：");
        int capacity = sc.nextInt();
        System.out.println("您购买饮料信息如下。");
        if (choice == 1) {
            System.out.println("请问是否需要配料(1.加糖 2.加奶 3.什么都不加):");
            int add = sc.nextInt();
            Coffee c1 = new Coffee();
            c1.setCapacity(capacity);
            switch (add) {
            case 1:
                c1.setAdd("加糖");
            break;
            case 2:
                c1.setAdd("加奶");
            break;
            case 3:
                c1.setAdd("什么都不加");
            break;
            }
            c1.show1();
        }else if(choice == 2){
            SpringWater s = new SpringWater(capacity); 
            s.show2();
        }else if (choice == 3) {
            System.out.println("请选择(1.可口可乐 2.百事可乐):");
            int brand = sc.nextInt();
            Cola c2 = new Cola();
            c2.setCapacity(capacity);
            switch (brand) {
            case 1:
                c2.setBrand("可口可乐");
            break;
            case 2:
                c2.setBrand("百事可乐");
            break;
            }
            c2.show3();
        }
    }
}

class Drink {
    private int capacity;
    public Drink(){}
    public Drink(int capacity){
        this.capacity = capacity;
    }
    public void setCapacity(int capacity){
        this.capacity = capacity;
    }
    public int getCapacity(){
        return capacity;
    }
}

class Coffee extends Drink {
    private String add;
    public Coffee(){}
    public Coffee(int capacity,String add){
        super(capacity);
        this.add = add;
    }
    public void setAdd(String add){
        this.add = add;
    }
    public String getAdd(){
        return add;
    }
    public void show1(){
        System.out.println("名称：咖啡" + "
" + "添加配料：" + getAdd() + "
" + "容量：" + getCapacity());
    }
}

class SpringWater extends Drink {
    public SpringWater(){}
    public SpringWater(int capacity){
        super(capacity);
    }
    public void show2(){
        System.out.println("名称：矿泉水" + "
" +  "容量：" + getCapacity());
    }
}

class Cola extends Drink {
    private String brand;
    public Cola(){}
    public Cola(int capacity,String brand){
        super(capacity);
        this.brand = brand;
    }
    public void setBrand(String brand){
        this.brand = brand;
    }
    public String getBrand(){
        return brand;
    }
    public void show3(){
        System.out.println("名称：" + getBrand() + "
" +  "容量：" + getCapacity());
    }
}