Computer Programming Concepts and Visual Basic David I. Schneider

Write #2, nom, yob
Else
foundFlag = True
End If
Loop
Close #1
Close #2
Kill “YOB.TXT”
Name “TEMP” As “YOB.TXT”
If Not foundFlag Then
MsgBox “The name was not found.”, , “”
Else
txtName.Text = “”
txtYOB.Text = “”
End If
End Sub
Private Sub DisplayYearOfBirth()
Dim nom As String, yob As Integer
‘Find the year of birth for the name in txtName
txtYOB.Text = “”
Open “YOB.TXT” For Input As #1
nom = “”
Do While (nom txtName.Text) And (Not EOF(1))
Input #1, nom, yob
Loop
If nom = txtName.Text Then
txtYOB.Text = Str(yob)
Else
MsgBox “Person is not in file.”, , “”
txtName.Text = “”
End If
Close #1
End Sub
[Run. After several names have been added, the file might look as shown in Figure 7-1.]
“Barbra”,1942
“Ringo”,1940
“Sylvester”,1946
FIGURE 7-1 Sample Contents of YOB.TXT
■ ERROR TRAPPING
If you try to Open a file on a diskette in drive A and there is no diskette in drive A, the program
will crash with the error message “Disk not ready.” Visual Basic has a device, called
error-trapping, for preventing this and many other types of errors. If an error occurs while
error-trapping is active, two things happen. An identifying number is assigned to the Number
property of an object called Err, and the program jumps to some lines of code called an errorhandling
routine, which takes corrective measures based on the value of Err.Number. Some
errors and the values they generate are as follows:
Sequential Files 221