定義一個類實現銀行賬戶的概念。包括的屬性有“賬號”和“存款餘額”，包括的方法有“存款”、“取款”、“查詢餘額”和“顯示賬號”。編寫一測試類，創建兩個不同的賬戶類的對象，並分別完成存款、取款、查詢餘額、顯示賬號等操作。
public class BankAccount {
String account ;
int account_num;
//構造函數
public BankAccount(String account,int account_num){
this.account=account;
this.account_num=account_num;
}
//存錢
public String addNum(int num){
account_num= account_num+num;
return "存錢成功";
}
//取錢
public String getNum(int num){
String result;
if(account_num>num){
account_num =account_num-num;
result="取錢成功";
}else{
result="賬戶餘額不足，還剩"+account_num;
}
return result;
}//顯示餘額
public String displayNum(){
return "賬戶餘額："+account_num;
}//顯示賬號
public String displayAccount(){
return "賬戶："+account;
}
public static void main(String[] args){
BankAccount Tom = new BankAccount("Tom",100);
BankAccount jane = new BankAccount("jane",50); //顯示他們各自的餘額
System.out.println("===顯示各自的餘額===");
System.out.println("Tom:"+Tom.displayNum());
System.out.println("jane:"+jane.displayNum()); //存錢取錢
System.out.println("===存錢取錢===");
System.out.println("Tom取50:"+Tom.getNum(50));
System.out.println("jane存200:"+jane.addNum(200)); //顯示賬戶 顯示餘額
System.out.println("===存錢取錢===");
System.out.println(Tom.displayAccount()+""+Tom.displayNum());
System.out.println(jane.displayAccount()+""+jane.displayNum());
}
}