Computer Programming Concepts and Visual Basic David I. Schneider

380 Computer Programming Concepts and Visual Basic
Private Sub cards_shuffling(n As Integer, nMax As Integer)
‘n is the number of the specific pass through the deck (1, 2, 3..)
‘nMax is the total number of passes when the deck is shuffled
picHand.Cls
picHand.Print “Shuffling Pass:”; n; “out of”; nMax
End Sub
Private Sub cmdQuit_Click()
End
End Sub
[Run, click on the Shuffle button, and click on the Deal button after the shuffling is complete.]
COMMENT
1. Example 1 illustrates “use” since the GoDown object of the bomb object
receives a plane object. In general, class A uses Class B if an object of class B
is sent a message by a property or method of class A, or a method or property
of class A returns, receives, or creates objects of class B.
SUMMARY
1. An object is an entity that stores data, has methods that manipulate the data, and
can trigger events. A class describes a group of similar objects. A method specifies
the way in which an object’s data are manipulated. An event is a change in
the state of an object.
2. Classes are defined in a separate module called a class module. Data is stored
in member variables and accessed by procedures called methods.
3. Property Let and Property Get procedures are used to set and retrieve values of
member variables. These procedures can also be used enforce constraints and
carry out validation.
4. The Initialize and Terminate event procedures are automatically invoked when
an object is created and falls out of scope, respectively.
5. An object variable is declared in the declarations section of a program with a
statement of the form Private objectName As className and created
with a statement of the form Set objectName = New className.
6. A collection is a convenient devise for grouping together diverse objects.
Objects are added to collections with the Add method and removed with the