java动手动脑（多态）

public class ParentChildTest {
	public static void main(String[] args) {
		Parent parent=new Parent();
		parent.printValue();
		Child child=new Child();
		child.printValue();
		
		parent=child;
		parent.printValue();//调用子类的方法，方法中是子类的变量
		
		parent.myValue++;
		parent.printValue();
		
		((Child)parent).myValue++;
		parent.printValue();
		
	}
}

class Parent{
	public int myValue=100;
	public void printValue() {
		System.out.println("Parent.printValue(),myValue="+myValue);
	}
}
class Child extends Parent{
	public int myValue=200;
	public void printValue() {
		System.out.println("Child.printValue(),myValue="+myValue);
	}
}

import java.util.Scanner;

 public class showAtm {
     @SuppressWarnings("resource")
     public static void main(String[] args) {
       ATM atm=new ATM();
       showAtm s=new showAtm();
       s.showFace();
       atm.select();
     }
     //显示菜单方法
   public static void showFace(){
         System.out.println("********************");
         System.out.println("    1.存款：");
         System.out.println("    2.取款：");
         System.out.println("    3.转账汇款：");
         System.out.println("    4.修改密码：");
         System.out.println("    5.查询余额：");
         System.out.println("********************");
         System.out.println("请选择：");
     }
 }
class PersonalAccount{
	 String account;
		String name;
		String date;
		String mima;
		double yue;

		PersonalAccount(String account,String name,String date,String mima,double yue){
			this.account=account;
			this.name=name;
			this.date=date;
			this.mima=mima;
			this.yue=yue;
		}
		String Getaccount()
		{
			return account;
		}
		String Getname()
		{
			return name;
		}
		String Getdata()
		{
			return date;
		}
		String Getmima()
		{
			return mima;
		}
		double Getyue()
		{
			return yue;
		}
		void Setaccount(String account)
		{
			this.account=account;
		}
		void Setname(String name)
		{
			this.name=name;
		}
		void Setdate(String date)
		{
			this.date=date;
		}
		void Setmima(String mima)
		{
			this.mima=mima;
		}
		void Setyue(double yue)
		{
			this.yue=yue;
		}
 }
 abstract class aATM{
     public abstract void QuKuan();//取款
     public abstract void CunKuan();//存款
     public abstract void Zhuanzhang();//转账
     public abstract void mima();//改密码
     public abstract void yue();//余额
 }
 class ATM extends aATM{
	 Scanner in = new Scanner(System.in);
    PersonalAccount A=new PersonalAccount("1234567890123","han","20161115","970318",1000);
    public void QuKuan(){
		System.out.println("可取款金额：");
		System.out.println("100元");
		System.out.println("500元");
		System.out.println("1000元");
		System.out.println("1500元");
		System.out.println("2000元");
		System.out.println("5000元");
		System.out.println("其他金额");
		System.out.println("请输入你要取款的金额：");
		double Q=in.nextDouble();
		if(A.yue-Q<0)
		{
			System.out.println("余额不足！");
		}
		else
		{
		System.out.println("取款成功！");
		 A.yue=A.yue-Q;
		
		}
	}
    public void CunKuan(){
		System.out.println("请输入存款金额：");
		double Q1=in.nextDouble();
		A.yue=A.yue+Q1;
	  }
    public void Zhuanzhang(){
		System.out.println("输入要转账的行号：");
		String H=in.next();
		System.out.println("你要转账的人的姓名是否为xxx?0:是,1:否");
		int X=in.nextInt();
		if(X==0)
		{
			System.out.println("请输入要转账的金额：");
			double Z=in.nextDouble();
			System.out.println("转账成功！");
			A.yue=A.yue-Z;
			System.out.println("您的余额为："+A.yue);
		}
		if(X==1)
		{
			System.out.println("卡号错误！");
		}
	}
    public void mima(){
		System.out.println("请输入您要修改的卡号：");
		String S=in.next();
	    if(A.Getaccount().equals(S))
	    {
	    	System.out.println("请输入原密码：");
	    	String S1=in.next();
	    	if(A.Getmima().equals(S1))
	    	{
	    		System.out.println("请输入新密码：");
	    		String S2=in.next();
	    		A.Setmima(S2);
	    		System.out.println("修改成功！");
	    	}
	    }
	}
    public void yue()
	{
		System.out.println("余额为："+A.yue);
	}
 void select(){
    boolean p=true;
	while(p == true)
	{
	Scanner in = new Scanner(System.in);
	System.out.println("请输入要执行的操作：");
	int m = in.nextInt();
	if(m == 1) 
	{
		QuKuan();
		continue;
	}
	if(m == 2)
	{
		CunKuan();
		continue;
		
	}
	if(m == 3)
	{
	    Zhuanzhang();
		continue;
	}
	if(m == 4)
	{
		mima();
		continue;
	}
	
	if(m == 5)
	  {
		yue();
		continue;
	  }
	else
	  {
		System.out.println("已退出系统！");
	    p = false;
	  }
	  in.close();
     }
  }
 }

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;

	}
}