Provide the dynamic range of values to Sub VBA Excel - vba

Question

I am trying to pass the line column value to the sub that will call a function to calculate some logic.
Before writing a sub I just defined a function and passed values manually to the function and dragging to the columns I needed.
But now I wanted to create something that will auto apply formula to a range of the column.
This is the code I am trying to do, maybe its not the best way but open for suggestions.
Function addDiscount(Qty, Price)
'
' addDiscount Macro
' adds Discount to given price and quantity
'
' Keyboard Shortcut: Ctrl+h
If (Qty >= 10 Or Price >= 200) Then
addDiscount = 30 * 0.01
Else
addDiscount = 0
End If
addDiscount = Application.Round(addDiscount, 2)
End Function
Sub insertAddDiscount()
Sheets("Sheet1").Select
Range("F9:F30").Select
Dim i As Integer
For i = 9 To 30
Selection.Formula = "=addDIscount($G$i,$E$i)"
Selection.Columns.AutoFit
Next i
End Sub

Answer 1

Since you are using a variable i inside the formula, you need to take it outside the ".
replace your line:
Selection.Formula = "=addDIscount($G$i,$E$i)"
with:
Selection.Formula = "=addDIscount($G" & i & ",$E" & i & ")"
However, let me suggest a solution, where you don't need to rely on Selecting the Range, and later on use Selection, but rely on fully qualified Range object (this will also shorten your code's run-time).
Sub insertAddDiscount()
Dim i As Long
With Sheets("Sheet1")
For i = 9 To 30
.Range("F" & i).Formula = "=addDIscount($G" & i & ",$E" & i & ")"
Next i
.Range("F9:F30").Columns.AutoFit
End With
End Sub