Computer Programming Concepts and Visual Basic David I. Schneider

Do While there are still data in the file
Get an item of data
Process the item
Loop
FIGURE 5-3 Pseudocode and Flowchart for Processing Data from a File
Sequential files can be quite large. Rather than list the entire contents, we typically
search the file for a specific piece of information.
EXAMPLE 2
Modify the program in Example 1 to search the telephone directory for a name specified by the user. If
the name does not appear in the directory, so notify the user.
SOLUTION:
We want to keep searching as long as there is no match and we have not reached the end of the list. Therefore,
the condition for the Do While statement is a compound logical expression with the operator And.
After the last pass through the loop, we will know whether the name was found and be able to display the
requested information.
Object Property Setting
frmPhone Caption Phone Number
lblName Caption Name to look up
txtName Text (blank)
cmdDisplay Caption Display Phone Number
picNumber
Private Sub cmdDisplay_Click()
Dim nom As String, phoneNum As String
Open “PHONE.TXT”For Input As #1
Do While (nom txtName.Text) And (Not EOF(1))
Input #1, nom, phoneNum
Loop
Close #1
picNumber.Cls
If nom = txtName.Text Then
picNumber.Print nom, phoneNum
Processing Lists of Data with Do Loops 137