Computer Programming Concepts and Visual Basic David I. Schneider

Remove method. The number of objects in a collection is determined with the
Count property and object is returned by the Item method using either a number
or a key.
7. Events are declared in the general declarations section of class module with a
statement of the form Public Event UserDefinedEvent (arg1, arg2,
...) and triggered with a RaiseEvent statement. In the form code, the declaration
statement for an object, must include the keyword WithEvents in order for
the events coming from the object to be processed.
8. Objects interact through use and containment.
PROGRAMMING PROJECTS
1. Son of Deep Blue. Write a program that plays a game of tic-tac-toe in which a
person competes with the computer. The game should be played in a control
array of nine labels. See Figure 12-3. After the user moves by placing an X in
a label, the program should determine the location for the O. The program
should use a tic-tac-toe object that raises events when a player moves and when
the game is over. The outcome of the game should be announced in a message
box.
FIGURE 12-3 Tic-Tac-Toe
2. Bank Account. Write a program to maintain a person’s Savings and Checking
accounts. The program should keep track of and display the balances in both
accounts, and maintain a list of transactions (deposits, withdrawals, fund transfers,
and check clearings) separately for each account. The two lists of transactions
should be stored in sequential files so that they will persist between
program sessions.
Consider the form in Figure 12-4. The two drop-down combo boxes should each
contain the items Checking and Savings. Each of the four frames corresponds
to a type of transaction. (When Savings is selected in the Account combo box,
the Check frame should disappear.) The user makes a transaction by typing data
into the text boxes of a frame and pressing the command button. The items
appearing in the transactions list box should correspond to the type of account
that has been selected. The caption of the second label in the Transfer frame
should toggle between “to Checking” and “to Savings” depending on the item
selected in the “Transfer from” combo box. If a transaction cannot be carried
out, a message (such as “Insufficient funds”) should be displayed.
Programming Projects 381