Need help with class inheritance

Question

I've got a class called jemAccount and i need to create a savings account class and a checking account class that inherit from it.
Here is the jemAccount:
public class jemAccount
protected String myName;
protected double myBalance;
protected double[] withdrawls = new double [50];
protected double[] deposits = new double [50];
protected int withIndex = 0;
protected int depIndex = 0;
public jemAccount ()
myBalance = 0;
public jemAccount (String newName)
myName = newName;
myBalance = 0;
public jemAccount (String newName, double newBal)
myName = newName;
myBalance = newBal;
public void setName(String newName)
myName = newName;
public double balance()
return myBalance;
public void withdrawl (double amount)
if (amount < 0)
myBalance += amount;
else
myBalance -= amount;
if (withIndex < 50)
withdrawls[withIndex] = amount;
withIndex++;
public void deposit (double amount)
if (amount > 0)
myBalance += amount;
if (depIndex < 50)
deposits[depIndex] = amount;
depIndex++;
public void printAccount()
System.out.println("Owner of account: " + myName);
System.out.println("Balance of account: " + myBalance);
System.out.println("Deposits: ");
for (int i = 0; i < depIndex; i++)
System.out.println(" " + deposits);
System.out.println("");
System.out.println("Withdrawls: ");
for (int i = 0; i < withIndex; i++)
System.out.println(" " + withdrawls[i]);
System.out.println("");
System.out.println("");
} // end of class jemAccount
Here are my requirements for the savings account class:
� Call the class "abcSaveAccount".
� Have this class inherit from "jemAccount"
� Add a float for keeping track of the yearly interest rate of the checking account. Call this class variable "interest" Make it protected.
� Add a public constructor for the savings account class. It should have one parameter, a float that initializes the new savings account class variable. This constructor should also call the parent class constructor with no arguments.
� Add a public method for calculating interest. Call it "calcInterest". Have it take one parameter, an integer which represents the number of months to calculate the interest for. This method should return a float, the result of the interest calculation. For example, if 30 months are entered as a parameter of 30, then 2 and one/half years of interest on the balance are calculated and returned.
Here are the requirements for the checking account class:
� Call the class "abcCheckAccount"
� Have this class inherit from "jemAccount"
� Add an array for keeping track of the checks you write. For now, just make this an array of 100 doubles, very similar to withdrawals
� Add a public constructor for the checking account class. It should have zero parameters. This constructor should also call the parent class constructor with no arguments.
� Add a new public method to your checking account class. Call it "writeCheck". This should take one double parameter. If the value of the parameter is positive, subtract the parameter from the balance, and copy the value into the "checks" array. (Keep the checks and withdrawals separate.) Else do nothing.
� Override the "printAccount" method. Have the checking account "printAccount" run its parent "class printAccount", then print out a list of the checks, after the list of the withdrawals.
Here's what i have so far for the savings account class:
public class abcSaveAccount extends jemAccount
protected float interest;
public void abcSaveAccount (float newSavings)
super ();
public calcInterest (int numberMonths)
return interest;
And here's what i have so far for the checking account class:
public class abcCheckAccount extends jemAccount
double[] checks = new doulbe[100];
public abcCheckAccount ()
super ();
public writeCheck (double value)
if (value >= 0)
balance = balance - value;

Answer 1

Few changes,
public class abcCheckAccount extends jemAccount {
     private double[] checks = new double[100];
     private int checkIndex;
     public abcCheckAccount() {
          super ();
          checkIndex=0;
     public void writeCheck (double value) {
          if ( value >= 0) {
               withdrawl(value);
               checks[checkIndex++]=value;
     public void printAccount() {
          super.printAccount();
          System.out.println("Checks:");
          for (int i = 0; i < checkIndex; i++) System.out.println("     "+checks[ i ]);
          System.out.println("");
          System.out.println("");
} // end of abcCheckAccount classand
public class abcprog {
   public static void main (String args[]) {
          abcCheckAccount check = new abcCheckAccount();
          check.setName("Sudha");
          check.deposit(1000.0);
          check.deposit(200.0);
          check.withdrawl(112.0);
          check.writeCheck(300.0);
          check.printAccount();
          abcSaveAccount save = new abcSaveAccount(6);
          save.setName("Mike");
          save.deposit(1000.0);
          save.withdrawl(112.0);
          save.printAccount();
          System.out.println("Calculated Interest : "+save.calcInterest(120));
}U can use this program to test your classes.
Sudha