A Flexible Account Class

File Account.java contains a definition for a simple bank account class with methods to withdraw, deposit, get the balance and account number, and return a String representation. Note that the constructor for this class creates a random account number. Save this class to your directory and study it to see how it works. Then modify it as follows:

1. Overload the constructor as follows:

public Account (double initBal, String owner, long number) - initializes the balance, owner, and account number as specified

public Account (double initBal, String owner) - initializes the balance and owner as specified; randomly generates the account number.

public Account (String owner) - initializes the owner as specified; sets the initial balance to 0 and randomly generates the account number.

2. Overload the withdraw method with one that also takes a fee and deducts that fee from the account.

File TestAccount.java contains a simple program that exercises these methods. Save it to your directory, study it to see what it does, and use it to test your modified Account class.

//************************************************************ 

// Account.java // // A bank account class with methods to deposit to, withdraw from, // change the name on, and get a String representation // of the account. 

//************************************************************ 

public class Account { 

private double balance; private String name; private long acctNum; 

//------------------------------------------------- 

//Constructor -- initializes balance, owner, and account number 

//------------------------------------------------- 

public Account(double initBal, String owner, long number) { 

balance = initBal; 

name = owner;

acctNum = number; 

}

//------------------------------------------------- 

// Checks to see if balance is sufficient for withdrawal. // If so, decrements balance by amount; if not, prints message. 

//------------------------------------------------- 

public void withdraw(double amount) { 

if (balance >= amount) 

else

balance -= amount; 

System.out.println("Insufficient funds"); 

}

//------------------------------------------------- 

// Adds deposit amount to balance. 

//------------------------------------------------- 

Chapter 7: Object-Oriented Design 109

public void deposit(double amount) 

{

balance += amount; 

}

//------------------------------------------------- 

// Returns balance. 

//------------------------------------------------- 

public double getBalance() { 

return balance; 

}

//------------------------------------------------- 

// Returns a string containing the name, account number, and balance. 

//------------------------------------------------- 

public String toString() { 

return "Name:" + name + 

" Account Number: " + acctNum + " Balance: " + balance; 

}

}

//************************************************************ 

// TestAccount.java // // A simple driver to test the overloaded methods of // the Account class. 

//************************************************************ 

import java.util.Scanner; 

 Scanner scan = new Scanner(System.in); 

public class TestAccount { 

public static void main(String[] args) { 

String name; double balance; long acctNum; Account acct; 

System.out.println("Enter account holder's first name"); 

name = scan.next(); 

acct = new Account(name); 

System.out.println("Account for " + name + ":"); System.out.println(acct); 

System.out.println(" Enter initial balance"); 

balance = scan.nextDouble(); 

acct = new Account(balance,name); 

System.out.println("Account for " + name + ":"); System.out.println(acct); 

System.out.println(" Enter account number"); acctNum = scan.nextLong(); acct = new Account(balance,name,acctNum); System.out.println("Account for " + name + ":"); System.out.println(acct); 

System.out.print(" Depositing 100 into account, balance is now "); 

acct.deposit(100); 

System.out.println(acct.getBalance()); System.out.print(" Withdrawing $25, balance is now "); 

acct.withdraw(25); 

System.out.println(acct.getBalance()); System.out.print(" Withdrawing $25 with $2 fee, balance is now "); 

acct.withdraw(25,2); 

System.out.println(acct.getBalance()); 

}

System.out.println(" Bye!"); 

}