继承应用

import java.util.Arrays;
/**
继承应用
*/
public class ExtendsDemo{
public static void main(String[] args){
Underwear u1 = new Underwear("背心","男士",35.5f);
Underwear u2 = new Underwear("胸垫","女士",98.0f);
Underwear u3 = new Underwear("内裤","男士",188.8f);
Underwear u4 = new Underwear("内裤","女士",298.0f);
Underwear u5 = new Underwear("bra","女士",58.0f);
/*
UnderwearManager um = new UnderwearManager();
um.add(u1);
um.add(u2);
um.add(u3);
um.add(u4);
um.add(u5);
Underwear[] us = um.getUnderwears();
for(Underwear u: us){
System.out.println(u.getInfo());
}
*/
/*
System.out.println("------------排序子类----------------");
PriceSortUnderwearManager um1 = new PriceSortUnderwearManager();
um1.add(u1);
um1.add(u2);
um1.add(u3);
um1.add(u4);
um1.add(u5);
Underwear[] us = um1.getUnderwears();
for(Underwear u: us){
System.out.println(u.getInfo());
}
*/
System.out.println("------------女士内衣子类---------------------");
WomenUnderwearManager wm = new WomenUnderwearManager();
wm.add(u1);
wm.add(u2);
wm.add(u3);
wm.add(u4);
wm.add(u5);
Underwear[] us = wm.getUnderwears();
for(Underwear u: us){
System.out.println(u.getInfo());
}


}
}


/**
内衣类
*/
class Underwear{
float price;//单价
String name;//名称
String sex;//男士或女士


public Underwear(String name,String sex,float price){
this.name = name;
this.sex = sex;
this.price = price;
}
public String getInfo(){
return sex+name+",RMB:"+price;
}
}


/**
内衣管理类
*/
class UnderwearManager{
private Underwear[] underwears = new Underwear[3];
private int count;//记录当前内衣数量,记数器


//添加内衣功能
public void add(Underwear u){
if(count>=underwears.length){
//数组动态扩展
int newlen = (underwears.length*3)/2+1;
underwears = Arrays.copyOf(underwears,newlen);
}
underwears[count] = u;
count++;
}

//输出所有的内衣信息
public Underwear[] getUnderwears(){
Underwear[] us = new Underwear[count];
for(int i=0;i<us.length;i++){
us[i] = underwears[i];
}
return us;
}
}


//实现按单价排序的子类
class PriceSortUnderwearManager extends UnderwearManager{
//重写父类的方法
public Underwear[] getUnderwears(){
Underwear[] us = super.getUnderwears();
Underwear temp = null;//临时的交换变量
for(int i=0;i<us.length-1;i++){
for(int j=0;j<us.length-1-i;j++){
if(us[j].price>us[j+1].price){
temp = us[j];
us[j] = us[j+1];
us[j+1] = temp;
}
}
}
return us;
}
}


//女士内衣管理
class WomenUnderwearManager extends UnderwearManager{
//重写父类的方法
public Underwear[] getUnderwears(){
Underwear[] src = super.getUnderwears();
//创建一个UnderwearManager对象，用于存储女士内衣
UnderwearManager um = new UnderwearManager();
for(int i=0;i<src.length;i++){
if("女士".equals(src[i].sex)){   //一般常量放前面变量放后面，为什么呢,因为避免空指针
um.add(src[i]);
}
}
return um.getUnderwears();


}

}

作业：

import java.util.Arrays;
/**
	作业
	1、设计一个宠物商店的宠物管理
	（1）创建一个宠物类（昵称，价格，种类）并派生各种宠物，
		 每种宠物都有各自吃食的方法。
	（2）创建一个商店类，可以根据种类显示该种类所有的宠物信息。

*/
public class HomeWork1{
	public static void main(String[] args){
		Dog d1 = new Dog("小白",2000.0f,"狗");
		Dog d2 = new Dog("小黑",1000.0f,"狗");
		Dog d3 = new Dog("小黄",800.0f,"狗");
		Cat c1 = new Cat("汤姆",200.0f,"猫");
		Cat c2 = new Cat("咪咪",1200.0f,"猫");

		PetShop ps = new PetShop();
		ps.add(d1);
		ps.add(d2);
		ps.add(d3);
		ps.add(c1);
		ps.add(c2);
		for(Pet p:ps.getPets()){
			System.out.println(p.getInfo());
			p.eat();
		}
		System.out.println("-----------查找狗--------------");
		Pet[] pets = ps.findByType("狗");
		for(Pet p:pets){
			System.out.println(p.getInfo());
			p.eat();
		}

	}
}

//宠物类
class Pet{
	String name;
	float price;
	String type;
	public Pet(String name,float price,String type){
		this.name = name;
		this.price = price;
		this.type = type;
	}
	//吃食方法
	public void eat(){
		System.out.println(type+"吃饭了");
	}
	//宠物信息
	public String getInfo(){
		return "我是一只"+type+",小伙伴们都叫我"+name+",喜欢我就把我带走吧,只需RMB"+price;
	}
}

//狗类
class Dog extends Pet{
	public Dog(String name,float price,String type){
		super(name,price,type);
	}
	//吃食方法
	public void eat(){
		System.out.println("我喜欢啃大棒骨");
	}
}
//猫类
class Cat extends Pet{
	public Cat(String name,float price,String type){
		super(name,price,type);
	}
	//吃食方法
	public void eat(){
		System.out.println("我喜欢吃鱼");
	}
}

//宠物商店
class PetShop{
	private Pet[] pets = new Pet[3];
	private int count;//记数器
	
	//添加
	public void add(Pet pet){
		if(count>=pets.length){
			int newlen = (pets.length*3)/2+1;
			pets = Arrays.copyOf(pets,newlen);
		}
		pets[count] = pet;
		count++;
	}

	//获取所有宠物
	public Pet[] getPets(){
		Pet[] ps = new Pet[count];
		for(int i=0;i<count;i++){
			ps[i] = pets[i];
		}
		return ps;
	}

	//根据宠物种类查找宠物信息
	public Pet[] findByType(String type){
		PetShop ps = new PetShop();
		for(int i=0;i<count;i++){
			if(pets[i].type.equals(type)){
				ps.add(pets[i]);
			}
		}
		return ps.getPets();
	}
}