大数据-java基础-第10章 面向对象——封装

1.银行存取钱的操作，实现密码登录，查询账户余额，以及取钱和存取的操作。 ①定义封装银行类，写出登录以及查询账户余额，以及取钱和存取的行为。

public class Atm { Scanner sc =new Scanner(System.in); String account = "lkk";// int password = 123456; int balance=5000; int a; int b; int count=0; boolean flag=true; //登录 public void accountShow() { while(count<3 & flag) { System.out.print("请输入您的账号："); String use = sc.next(); System.out.print("请输入您的密码："); int pass =sc.nextInt(); if(use.equals(account)&&pass==password) { System.out.print("登录成功!!!"); ba(); flag=false; }else{ System.out.println("您输入的账号不存在："+"账号为："+use+"密码为："+pass); count++; flag=true; } } } //查询账户余额，以及取钱和存取的行为 public void ba() { System.out.print("\n请选择你要操作的手续："); String procedure = sc.next(); if(procedure.equals("存款")) { System.out.print("请输入你存款金额："); int money=sc.nextInt(); balance=balance+money; System.out.print("存款后的金额："+balance); }else if (procedure.equals("取款")) { System.out.print("请输入你取款金额："); int money1=sc.nextInt(); if(money1>balance) { System.out.print("金额不足："); }else { balance=balance-money1; System.out.print("取款后的金额："+balance); } }else if(procedure.equals("查询")) { System.out.print("您的账号余额为："+balance); } } }

②测试类的编写（以在银行类中封装好了方法，在测试时可以直接调用）

public class AtmText { public static void main(String[] args) { // TODO Auto-generated method stub Atm at=new Atm(); at.accountShow(); } }

2.利用封装方法实现冒泡排序 ①定义类，写出冒泡的方法

public class Bubble { Scanner sc = new Scanner(System.in); public int num() { System.out.print("请输入排序数字的个数："); int num=sc.nextInt(); return num; } public void arr() { int arr [] = new int[num()]; for (int i= 0;i <arr.length;i++) { System.out.print("请输入第"+(i+1)+"位数字："); arr[i]=sc.nextInt(); } System.out.print("输入数字为： "); for(int n :arr) { System.out.print(n+" "); } System.out.print("\n升序后的数组为： "); for(int i = 0;i<arr.length;i++) { for (int j = 0;j<arr.length-1;j++) { if(arr[j]>arr[j+1]) { int temp =arr[j]; arr[j]=arr[j+1]; arr[j+1]=temp; } } } for(int n1 :arr) { System.out.print(n1+" "); } } }

②测试类的编写

public class BubbleText { public static void main(String[] args) { // TODO Auto-generated method stub Bubble bu=new Bubble(); bu.arr(); } }

3.利用封装实现简单四则运算 答：①定义类，写出四则运算法则

public class Count { int a; int b; public void sumShow() { System.out.println("求和为："); } public int sum() { int sum =a+b; return sum; } public void yuShow() { System.out.println("余数为："); } public double yu() { double yu =a%b; return yu; } public int cha() { int cha =a-b; return cha; } public int sheng() { int sheng =a*b; return sheng; } public void shangShow() { System.out.println("商为："); } public double shang() { double shang =a/b; return shang; } char c; public void panDuan() { switch (c) { case '+' : System.out.print(sum()); break; case '-' : System.out.print(cha()); break; case '*' : System.out.print(sheng()); break; case '/' : System.out.print(shang()); break; case '%' : System.out.print(yu()); break; } } }

②测试类的编写

public class CountText { public static void main(String[] args) { // TODO Auto-generated method stub Scanner sn =new Scanner(System.in); System.out.print("请输入您想进行的四则运算符："); Count cs =new Count(); cs.c =sn.next().charAt(0); System.out.print("请输入第一个数 a:"); cs.a =sn.nextInt(); System.out.print("请输入第二个数 b:"); cs.b =sn.nextInt(); cs.panDuan(); } }