Private Funtion(....) As .... {VB}

schoe

A bookstore vendor sells storybook (RM15 each), magazine (RM10 each) and academic reference ( RM45 each) to the customer. Write a program to calculate a customer total cost when user click on the "Total Cost" command button.The program shouild request the quantity of each item ordered from a sub procedure "Quantity" where the parameter of this procedure are pass by reference.calculate the total cost with a fucntion " Total" and use a message box to display the result. You have to use the following variables in your program :

Module_level variables : intStoryQty, intMagazineQty, intAcademicQty
Local_level variables : sngTotalCost
Constant variables: sngSTORYPRICE, sngMAGAZINEPRCIE, sngACADEMICPRICE

Private Sub cmdTotal_Click()
Const sngSTORYPRICE As Single = 15
Const sngMAGAZINEPRICE As Single = 10
Const sngACADEMICPRICE As Single = 45

Call Quantity(intStoryQty, intMagazineQty, intAcademicQty)

ComputeTotal = Total(txtStoryBook, txtMagazine, txtAcademic)

End Sub


Private Sub Quantity(ByRef intStoryQty As Integer, ByRef intMagazineQty As Integer, ByRef intAcademicQty As Integer)
    intStoryQty = Val(txtStoryBook.Text)
    intMagazineQty = Val(txtMagazine.Text)
    intAcademicQty = Val(txtAcademic.Text)
   
End Sub


Private Function Total(intStoryQty As Integer, intMagazineQty As Integer, intAcademicQty As Integer) As Integer

Dim sngTotalCost As Single

sngTotalCost = intStoryQty * sngSTORYPRICE + intMagazineQty * sngMAGAZINEPRICE + intAcademictQty * sngACADEMICPRICE
MsgBox " Total Cost is " & sngTotalCost, vbOKOnly, "Result"
End Function


请问我做错什么？

试试看这个：

Const sngSTORYPRICE As Single = 15
Const sngMAGAZINEPRICE As Single = 10
Const sngACADEMICPRICE As Single = 45

Public intStoryQty as integer
Public intMagazineQty as integer
Public intAcademicQty as integer

Private Sub cmdTotal_Click()
  intStoryQty = 0
  intMagazineQty = 0
  intAcademicQty = 0

  Call Quantity(intStoryQty, intMagazineQty, intAcademicQty)

  MsgBox "Total Cost is " & Total(), vbOKOnly, "Result"

End Sub

Private Sub Quantity(ByRef intStoryQty As Integer, ByRef intMagazineQty As Integer,ByRef intAcademicQty As Integer)
    intStoryQty = Val(txtStoryBook.Text)
    intMagazineQty = Val(txtMagazine.Text)
    intAcademicQty = Val(txtAcademic.Text)
End Sub

Private Function Total() As Integer
  Dim sngTotalCost As Single

  sngTotalCost = intStoryQty * sngSTORYPRICE + intMagazineQty * sngMAGAZINEPRICE + intAcademictQty * sngACADEMICPRICE

  Quantity = sngTotalCost
End Function