  /** 
    A bank account has a balance that can be changed by 
     deposits and withdrawals. 
  */ 
  public class BankAccount 
  { 
     /** 
   Constructs a bank account with a zero balance. 
    @param anAccountNumber the account number for this account 
    */ 
    public BankAccount(int anAccountNumber) 
    { 
    accountNumber = anAccountNumber; 
    balance = 0; 
    } 
 
    /** 
       Constructs a bank account with a given balance. 
    @param anAccountNumber the account number for this account 
    @param initialBalance the initial balance 
    */ 
    public BankAccount(int anAccountNumber, double initialBalance) 
    { 
    accountNumber = anAccountNumber; 
    balance = initialBalance; 
    } 
 
    /** 
  Gets the account number of this bank account. 
    @return the account number 
   */ 
    public int getAccountNumber() 
    { 
   return accountNumber; 
   } 
 
    /** 
  Deposits money into the bank account. 
    @param amount the amount to deposit 
    */ 
    public void deposit(double amount) 
    { 
   double newBalance = balance + amount; 44    balance = newBalance; 
    } 
 
    /** 
   Withdraws money from the bank account. 
    @param amount the amount to withdraw 
    */ 
    public void withdraw(double amount) 
    { 
       double newBalance = balance - amount; 
    balance = newBalance; 
    } 
 
    /** 
   Gets the current balance of the bank account. 
    @return the current balance 
    */ 
    public double getBalance() 
    { 
   return balance; 
    } 
 
    private int accountNumber; 
    private double balance; 
  } 
