课后作业一：接口多态：使用接口代替抽象基类一、源代码package zoo4;
import java.util.Vector;
public class Zoo2 {
public static void main(String args[]) {
Feeder f = new Feeder("小李");
Vector<Animal> ans = new Vector<Animal>();//可随时向其中加入或移除对象
//饲养员小李喂养一只狮子
ans.add(new Lion());
//饲养员小李喂养十只猴子
for (int i = 0; i < 10; i++) {
ans.add(new Monkey());
}
//饲养员小李喂养5只鸽子
for (int i = 0; i < 5; i++) {
ans.add(new Pigeon());
}
f.feedAnimals(ans);
}
}
class Feeder {
public String name;
Feeder(String name) {
this.name = name;
}
public void feedAnimals(Vector<Animal> ans) {
for (Animal an : ans) {
an.eat();
}
}
}
interface Animal {
public void eat();
}
class Lion implements Animal {
public void eat() {
System.out.println("我不吃肉谁敢吃肉！");
}
}
class Monkey implements Animal {
public void eat() {
System.out.println("我什么都吃，尤其喜欢香蕉。");
}
}
class Pigeon implements Animal {
public void eat() {
System.out.println("我要减肥，所以每天只吃一点大米。");
}
}
二、实验运行截图
课后作业二：用多态的方法模拟ATM操作流程
1.源程序：
package Work;
//接口多态：使用接口代替抽象基类
import java.util.Scanner;
import java.util.Vector;
public class ATM{
static AccountY stu[]=new Account[500];
public static void main(String[] args) {
//主界面(5个用户)
stu[0]=new Account("20153149","流刘雨鑫","2016/11/16","12346",100);
stu[1]=new Account("20153150","刘","2016/11/15","li",2000);
stu[2]=new Account("20153151","啦啦子","2016/11/15","muzi",3000);
stu[3]=new Account("20153149","咦米","2016/11/15","mimi",5000);
stu[4]=new Account("20153148","哦哦暑","2016/11/15","xiaxiao",40);
String key;
Scanner scan=new Scanner(System.in);
Scanner scan1=new Scanner(System.in);
Scanner scan2=new Scanner(System.in);
Scanner scan3=new Scanner(System.in);
int num=0;
int k=1;
System.out.println("请输入密码：");
key=scan.nextLine();
int b=0;
for(int i=0;i< 5;i++)
{ if(!key.equals(stu[i].getKey()))
{ b++;}}
if(b>=5){
System.out.print("该卡已被锁定，无法操作");
}
else
for(int i=0;i< 5;i++)
{
if(key.equals(stu[i].getKey()))
{
while(k==1)
{
System.out.println();
System.out.print("1.存款 2.取款 3.转账汇款 4.修改密码 5.查询余额 6.退卡");
System.out.println();
System.out.print("请选择：");
num=scan1.nextInt();
if(num==6)
{ System.out.println("卡已成功退出！请拿卡！");
break;
}
switch(num)
{
case 1://存款
double m;
System.out.print("请输入存入的金额：");
m=scan2.nextDouble();
stu[i].cun(m);
break;
case 2://取款
int numm;
System.out.print("100元\t500元\t1000元\t1500元\t2000元\t5000元\t其他金额\n"
+ "1.退卡");
System.out.println();
System.out.print("请选择：");
numm=scan3.nextInt();
if(numm==1) break;
else
stu[i].qu(numm);break;
case 3://转账汇款
String nummm;
double cc;
int n;
System.out.print("请输入转账行号：");
nummm=scan.nextLine();
/*boolean b=true;
for(int j=0;j<5;j++)
{if(!nummm.equals(stu[j].getNum()))
{
b=false;
}}
if(b==false){
System.out.println("信息错误！");
}*/
for(int j=0;j<5;j++)
if(nummm.equals(stu[j].getNum()))
{
System.out.print("请输入转账金额：");
cc=scan.nextDouble();
System.out.print("请确认（1确认,0取消）");
n=scan.nextInt();
if(n==1)
{
stu[i].qu(cc);
stu[j].cun(cc);
System.out.print("转账成功!");
}
else if(n==0){
System.out.print("已取消！");
}
else{
System.out.print("发生错误！");
}
}
break;
case 4:
String kk;
System.out.print("请输入修改的密码：");
kk=scan.nextLine();
stu[i].setKey(kk);
break;
case 5:
System.out.print("余额为："+stu[i].getMoney());
break;
case 6:
break;
}
}
}}
}
}
abstract class AccountY
{
public abstract String getNum();
public abstract void setKey(String s);
public abstract String getKey();
public abstract double getMoney();
public abstract void cun(double m);
public abstract void qu(double m);
}
class Account extends AccountY{
private String num;//长度为11，由数字和字符组合
private String name;//用户的姓名
private String Date;//操作日期
private String key;//账户密码
private double money;//当前余额
public Account(String n,String a,String b,String c,double d){num=n;name=a;Date=b;key=c;money=d;}
public String getNum(){return num;}
public String getName(){return name;}
public String getDate(){return Date;}
public void setKey(String s){
key=s;
}
public String getKey(){return key;}
public double getMoney(){return money;}
public void cun(double m){
if(m<=200000)
money+=m;
else
{System.out.println("超出限额！");}
}
public void qu(double m){
if(m<money)
money-=m;
else
System.out.println("超出余额！");
}
}
二、实验结果截图
验证：
①TestInstanceof.java
代码
public class TestInstanceof
{
public static void main(String[] args)
{
//声明hello时使用Object类，则hello的编译类型是Object，Object是所有类的父类
//但hello变量的实际类型是String
Object hello = "Hello";
//String是Object类的子类，所以返回true。
System.out.println("字符串是否是Object类的实例：" + (hello instanceof Object));
//返回true。
System.out.println("字符串是否是String类的实例：" + (hello instanceof String));
//返回false。
System.out.println("字符串是否是Math类的实例：" + (hello instanceof Math));
//String实现了Comparable接口，所以返回true。
System.out.println("字符串是否是Comparable接口的实例：" + (hello instanceof Comparable));
String a = "Hello";
//String类既不是Math类，也不是Math类的父类，所以下面代码编译无法通过
//System.out.println("字符串是否是Math类的实例：" + (a instanceof Math));
}
}
运行结果截图：
②TestCast.java
代码如下：
class Mammal{}
class Dog extends Mammal {}
class Cat extends Mammal{}
public class TestCast
{
public static void main(String args[])
{
Mammal m;
Dog d=new Dog();
Cat c=new Cat();
m=d;
//d=m;
d=(Dog)m;
//d=c;
//c=(Cat)m;
}
}
运行结果没有出错！
③Zoo.java
代码如下：
package zoo4;
import java.util.Vector;
public class Zoo {
public static void main(String args[]) {
Feeder f = new Feeder("小李");
Vector<Animal> ans = new Vector<Animal>();//可随时向其中加入或移除对象
//饲养员小李喂养一只狮子
ans.add(new Lion());
//饲养员小李喂养十只猴子
for (int i = 0; i < 10; i++) {
ans.add(new Monkey());
}
//饲养员小李喂养5只鸽子
for (int i = 0; i < 5; i++) {
ans.add(new Pigeon());
}
f.feedAnimals(ans);
}
}
class Feeder {
public String name;
Feeder(String name) {
this.name = name;
}
public void feedAnimals(Vector<Animal> ans) {
for (Animal an : ans) {
an.eat();
}
}
}
abstract class Animal {
public abstract void eat();
}
class Lion extends Animal {
public void eat() {
System.out.println("我不吃肉谁敢吃肉！");
}
}
class Monkey extends Animal {
public void eat() {
System.out.println("我什么都吃，尤其喜欢香蕉。");
}
}
class Pigeon extends Animal {
public void eat() {
System.out.println("我要减肥，所以每天只吃一点大米。");
}
}
运行结果截图：
时间： 2024-10-12 15:42:46