Computer Programming Concepts and Visual Basic David I. Schneider

184 Computer Programming Concepts and Visual Basic
COMMENTS
1. In the discussion and examples of control arrays, the initial index was always 0.
For a particular application it may be more natural to have the lowest index of
a control array be 1 or even 1995. To achieve this when creating just the first
element at design time and the remaining controls at run time, set the Index
property of the first element to the desired lowest index value at design time,
then Load the other elements using the desired indexes at run time. (The Load
statement copies the properties of the element with the lowest index, whatever
that lowest index may be.) For example, at design time you might create
txtSales(1995) and then at run time execute the statements
For yearNum = 1996 to 2005
Load txtSales(yearNum)
Next yearNum
To create an entire control array at design time with indexes starting at a value
other than 0, first create the control array using an initial index of 0. Once all
elements have been created, use the Properties window to adjust the index of
each element of the control array, starting with the element having the highest
index.
6.4 SORTING AND SEARCHING
A sort is an algorithm for ordering an array. Of the many different techniques for sorting an
array we discuss two, the bubble sort and the Shell sort. Both require the interchange of values
stored in a pair of variables. If var1, var2, and temp are all variables of the same data type
(such as all String), then the statements
temp = var1
var1 = var2
var2 = temp
assign var1’s value to var2, and var2’s value to var1.
EXAMPLE 1
Write a program to alphabetize two words supplied in text boxes.
SOLUTION:
Private Sub cmdAlphabetize_Click()
Dim firstWord As String, secondWord As String, temp As String
‘Alphabetize two words
firstWord = txtFirstWord.Text
secondWord = txtSecondWord.Text
If firstWord > secondWord Then
temp = firstWord
firstWord = secondWord
secondWord = temp
End If
picResult.Cls
picResult.Print firstWord; “ before ”; secondWord
End Sub
[Run, type the following text shown into the text boxes, and click the command button.]