Read pages 154-158 before next lab period.

Hand in part A of Homework #3 (see homework description below).

1. First copy the merryxmas Vaccine from the classes server onto your disk. Open the vaccine and use it to check all the stacks on your disk for the merryxmas virus.

2. Finish up the first part of lab 5 if you didn't on Thursday. When you finish, show us your find/replace stack and if you didn't finish it last lab, your greeting card.

3. Do Lab exercises 4.1 and 4.2 on page 144 in your book. When you have finished, call one of us over to show us your modified stack.

4. If there is still time remaining in class, modify the stack No Account so that it allows the user to request that the account information for a given account id be displayed in the card field "results." This will require creating a new field where the user can enter the account id, and a new button which will search through card field "data" and display in card field "results" the appropriate line from card field "data."

1. Algorithms (Part A below) are due at the beginning of lab on Thursday, Sept. 25. These are submitted in printed form.

2. The modified stack (Part B below) is due at the beginning of lab on Thursday, Oct. 2. This is submitted on a diskette.

• Include your name and the date in comment statements at the beginning of each modified script.
• Document all modifications you make using program comments (as part of your scripts).
• Include a title and clear labels as a part of each output display (as seen in card field results).

1. Edit the script of button "Average balance" so that, after calculating and displaying the average balance, it then determines and displays the number of accounts with greater than average balances and the number of accounts whose balances are no more than average. The new calculations should be done in a separate handler which can be called (invoked) from the MouseUp handler. You will need to use a parameter to pass the current average balance from the MouseUp handler to your new handler. Your new handler should also display the Names, IDs and Balances (in this order) for the accounts, grouped according to whether the balance is above or below average.

2. Create a new button that calculates and displays in field "Results" a listing of IDs, #Payments Remaining and Balances (in this order) for accounts that have less than six payments remaining. Name this button appropriately.

Problem:

Determine and display the average value of a list of numbers.

First pass solution:

Divide the sum of the numbers on the list by how many numbers the list contains; display this quotient.

After some refinement, an algorithm to solve this problem might look like:

1. Initialize a counter to 0. ("counter" tells how many of the list's numbers have been seen so far.)

2. Initialize a total to 0. ("total" is the sum of those numbers seen so far.)

3. For each number in the list,
   • add the number to the current total and
   • add 1 to the current counter.

4. After all the numbers have been seen, divide the total by the counter.

5. Display this as the answer.