VERSION 5.00
Begin VB.Form frmAverage 
   Caption         =   "Fig. 4.12: Class Average Program"
   ClientHeight    =   1890
   ClientLeft      =   2895
   ClientTop       =   2535
   ClientWidth     =   4380
   BeginProperty Font 
      Name            =   "MS Sans Serif"
      Size            =   8.25
      Charset         =   0
      Weight          =   700
      Underline       =   0   'False
      Italic          =   0   'False
      Strikethrough   =   0   'False
   EndProperty
   ForeColor       =   &H80000008&
   LinkTopic       =   "Form1"
   PaletteMode     =   1  'UseZOrder
   ScaleHeight     =   1890
   ScaleWidth      =   4380
   Begin VB.CommandButton cmdExit 
      BackColor       =   &H80000005&
      Caption         =   "Exit"
      BeginProperty Font 
         Name            =   "MS Sans Serif"
         Size            =   12
         Charset         =   0
         Weight          =   700
         Underline       =   0   'False
         Italic          =   0   'False
         Strikethrough   =   0   'False
      EndProperty
      Height          =   735
      Left            =   2640
      TabIndex        =   2
      Top             =   960
      Width           =   1455
   End
   Begin VB.CommandButton cmdEnterData 
      BackColor       =   &H80000005&
      Caption         =   "Enter Grades"
      BeginProperty Font 
         Name            =   "MS Sans Serif"
         Size            =   12
         Charset         =   0
         Weight          =   700
         Underline       =   0   'False
         Italic          =   0   'False
         Strikethrough   =   0   'False
      EndProperty
      Height          =   735
      Left            =   120
      TabIndex        =   0
      Top             =   945
      Width           =   1935
   End
   Begin VB.Label lblAverage 
      Caption         =   "Press Enter Grades to Start."
      BeginProperty Font 
         Name            =   "MS Sans Serif"
         Size            =   12
         Charset         =   0
         Weight          =   700
         Underline       =   0   'False
         Italic          =   0   'False
         Strikethrough   =   0   'False
      EndProperty
      Height          =   375
      Left            =   120
      TabIndex        =   1
      Top             =   240
      Width           =   3975
   End
End
Attribute VB_Name = "frmAverage"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = False
' Fig. 4.12
' Class average program with
' sentinel-controlled repetition
Option Explicit    ' General declaration

Private Sub cmdEnterData_Click()
   Dim total As Integer     ' Sum of all grades input
   Dim counter As Integer   ' Number of grades input
   Dim grade As Integer     ' Current grade
   Dim average As Single    ' Floating-point average
   Dim message As String    ' Text displayed in Label
   
   ' Initialization phase
   total = 0
   counter = 0

   ' Processing phase
   grade = InputBox("Enter grade: -1 to end", "VBHTP")

   ' Loop until grade has a -1 value
   Do Until grade = -1
      total = total + grade      ' Add grade to total
      counter = counter + 1      ' Increment counter
      
      ' Input the next grade. When -1 is assigned,
      ' the loop continuation condition becomes True
      grade = InputBox("Enter grade: -1 to end", "VBHTP")
   Loop

   ' Termination phase
   If counter <> 0 Then        ' Prevent division by zero
     average = total / counter ' Floating-point division
     message = "Class average is "
     
     ' Format average and concatenate to message
     message = message & Format$(average, "Fixed")
     lblAverage.Caption = message
   Else    ' counter is 0
     lblAverage.Caption = "No grades were entered."
   End If

End Sub

Private Sub cmdExit_Click()
   End
End Sub