Question

ATM Revisited

In Java, design a subclass of the Account class called GoldAccount. It is still an Account class, however it has an additional field and some additional functionality. But it will still retain all the behavior of the Account class.

Write a class called GoldAccount. This class will have an additional private field called bonusPoints. This field will require no get or set methods. But it will need to be initialized to 100 in the constructor. Thereafter, after a deposit to the gold account, bonusPoints will be increased by a random number between 100 and 200. This somewhat simulates a preferred client for the bank. If the bonusPoints increase to over 1000 then the gold account gets an additional $10 added to it, and bonusPoints is reduced by 1000. This is the only new behavior that we are adding to our class.

The benefit of inheritance is that this subclass, GoldAccount, does not have to re-write everything that is in the Accountsclass. Everything that is in Accounts gets included in GoldAccount simply by virtue of it’s being a subclass of Accounts. So all we need to add to our GoldAccount is this extra field called bonusPoints.

The other method to over ride is the toString() method. In the GoldAccount class, the toString() method needs to include the number of bonus points accrued. The gold account toString() method will call the superclass’ toString() method and then append the number of bonus points to the returned string.

GoldAccount Class

The GoldAccount class is not as long as the Accounts class. It consists of a single field, a constructor, and two methods. Again, the new field is called bonusPoints. The constructor will call the superclass constructor with the keyword super(), and then initialize bonusPoints to 100.

The two methods over ride methods of the Accounts class. The first method to over ride is the deposit() method. The GoldAccount deposit() method will make sure that the user has validated himself and then will add the deposit amount to the balance through the superclass’ deposit() method (again using the keyword super). It will then add a random number (between 100 to 200, inclusive) to bonusPoints. If bonusPoints goes over 1000 then an additional $10 will be added to the balance. Again, through the superclass’ deposit() method. The method will print to the screen in this case to alert the user that he has just been awarded an additional $10. Be sure to then subtract 1000 from bonusPoints.

My Account Class

import java.security.SecureRandom;

public class Account {

private String name;

private int pword;

private double balance;

private boolean validated;

private static int numOfAccounts = 0;

public Account(){

// assign password equal to account number

pword = numOfAccounts;

// set balance equal to random number between 0 and 1000

SecureRandom rng = new SecureRandom();

balance = rng.nextDouble()*1000;

// initially account is not validated

validated = false;

// assign name starting with A, B, C, ..., A1, B1, C1, ....

if(numOfAccounts < 25) name = Character.toString((char)(numOfAccounts+ 65));

else{

int multiple = numOfAccounts/26;

//name = Character.toString((char)multiple);

name = Character.toString((char)((numOfAccounts - 26*multiple)+65)) + multiple;

}

numOfAccounts++;

}

public boolean validate(int pword_guess){

if(pword_guess == pword) validated = true;

else validated = false;

return validated;

}

public boolean withdraw(double d) {

if(validated){

if(d > balance) return false;

else{

balance -= d;

return true;

}

}else return false;

}

public void deposit(double d){

if(validated) balance += d;

}

public double getBalance(){

if(validated) return balance;

else return 0;

}

public String getName(){

return name;

}

public boolean getValidated(){

return validated;

}

@Override

public String toString(){

if(validated)

return "\n\tName: " + name + "\tPassword: " + pword +"\tbalance: " + "$" + String.format("%.2f", balance)+ "\tValidated: " + validated;

else return "";

}

}

Answer 1

GoldAccount.java:

public class GoldAccount extends Account
{
private int bonusPoints;

public GoldAccount()
{
super();
bonusPoints = 100;
}

@Override
public void deposit(double d)
{
if (super.getValidated())
{
super.deposit(d);

// Math.random returns a value in [0, 1)
// Changing it to a different range, 100-200 (both inclusive)
bonusPoints += (int)(Math.random()*(201-100) + 100);
if (bonusPoints > 1000)
{
super.deposit(10);

System.out.println("\nCustomer has been awarded an additional $10!");
bonusPoints -= 1000;
}
}
}

@Override
public String toString()
{
return super.toString() + "\tBonusPoints: " + bonusPoints;
}
}

Driver.java:

// Driver class for testing
public class Driver
{
public static void main(String[] args)
{
GoldAccount gacc1 = new GoldAccount();
GoldAccount gacc2 = new GoldAccount();

System.out.println(gacc1.validate(1));
System.out.println(gacc1.validate(0));

System.out.println(gacc2);
System.out.println(gacc2.validate(1));
System.out.println(gacc2);

System.out.println();
gacc1.deposit(100);
gacc1.deposit(323);
gacc1.deposit(200);
System.out.println(gacc1);

gacc1.deposit(100);
gacc1.deposit(100);
gacc1.deposit(100);
System.out.println(gacc1);
}
}

Output:

avac -d bin *.java

Administrator: CWindows System32\cmd.exe java Driver false true BonusPoints: 100 true Name: B Password: 1 Balance: $829.77 Validated: true BonusPoints: 100 Name: A Password: Balance: $1139.12 Customer has been awarded an additional $10! Name: A Password: Balance: $1449.12 Validated: true BonusPoints: 602 Validated: true BonusPoints: 97