Computer Programming Concepts and Visual Basic David I. Schneider

The range of an array need not just begin with 1. A statement of the form
Dim arrayName(m To n) As varType
where m is less than or equal to n, creates an array with elements arrayName(m), arrayName(m
+ 1), arrayName(m + 2), . . . , arrayName(n). The same holds for ReDim.
EXAMPLE 6
The following program segment stores the names of the 13th, 14th, and 15th Chief Justices of the U.S.
Supreme Court in the array pictured in Figure 6-4.
‘Place names of last three Chief Justices in an array
Dim chiefJustice(13 To 15) As String
Private Sub Form_Load()
chiefJustice(13) = “Earl Warren”
chiefJustice(14) = “Warren Burger”
chiefJustice(15) = “William Rehnquist”
End Sub
FIGURE 6-4 The Array Created by Example 6
An array can be used as either a checklist or frequency table, as in the next example. The
function Asc associates each character with its position in the ANSI table.
EXAMPLE 7
The following program requests a sentence as input and records the number of occurrences of each letter
of the alphabet. The array charCount( ) has range Asc(“A”) To Asc(“Z”), that is, 65 To 90. The number
of occurrences of each letter is stored in the element whose subscript is the ANSI value of the uppercase
letter.
Private Sub cmdAnalyze_Click()
Dim index As Integer, letterNum As Integer, sentence As String
Dim letter As String, column As Integer
‘Count occurrences of different letters in a sentence
ReDim charCount(Asc(“A”) To Asc(“Z”)) As Integer
For index = Asc(“A”) To Asc(“Z”)
charCount(index) = 0
Next index
‘Consider and tally each letter of sentence
sentence = UCase(txtSentence.Text)
For letterNum = 1 To Len(sentence)
letter = Mid(sentence, letterNum, 1)
If (letter >= “A”) And (letter