Computer Programming Concepts and Visual Basic David I. Schneider

164 Computer Programming Concepts and Visual Basic
FIGURE 6-2 The Array TeamName( ) of Example 1
In Example 1, the array teamName was assigned values within the cmdWhoWon_Click
event procedure. Every time the command button is clicked, the values are reassigned to the
array. This manner of assigning values to an array can be very inefficient, especially in programs
with large arrays where the task of the program (in Example 1, looking up a fact) may
be repeated numerous times for different user input. When, as in Example 1, the data to be
placed in an array are known at the time the program first begins to run, a more efficient
location for the statements that fill the array is in Visual Basic’s Form_Load event procedure.
The Form_Load event procedure is executed by Visual Basic as soon as the program is run,
and this execution is guaranteed to occur before the execution of any other event or general
procedure in the program. Example 2 uses the Form_Load procedure to improve on
Example 1.
EXAMPLE 2
Modify Example 1 to request the name of a baseball team as input and search the array to determine
whether or not the team name appears in the array. Load the array values only once.
’Create array for five strings
Dim teamName(1 To 5) As String ‘in (Declarations) section of (General)
Private Sub cmdDidTheyWin_Click()
Dim team As String, foundFlag As Boolean, n As Integer
’Search for an entry in a list of strings
team = txtName.Text
foundFlag = False
n = 0
Do
n = n + 1
If UCase(teamName(n)) = UCase(team) Then
foundFlag = True
End If
Loop Until (foundFlag = True) Or (n = 5)
‘Above line can be replaced with Loop Until (foundFlag) or (n = 5)
picWinner.Cls
If foundFlag = False Then ‘Can be replaced by If Not foundFlag Then
picWinner.Print “The ”; team; “ did not win any”;
picWinner.Print “ of the first five World Series.”
Else
picWinner.Print “The ”; teamName(n); “ won World Series number”; n
End If
End Sub
Private Sub Form_Load()
’Fill array with World Series winners
teamName(1) = “Red Sox”
teamName(2) = “Giants”
teamName(3) = “White Sox”
teamName(4) = “Cubs”
teamName(5) = “Cubs”