Excel macro cell address increase - vba

Question

Can i increase the cell address by using macro?
I'm implementing excel cell color matching function.
Example:
When i change the cell "A1" to red, cell "D1" will change to red.
if change "C1" to red, "F1" will change to red too. All need to increase 3 column.
Now i just need to modify the "c.Address" by + 3 so the cell will go do D1.
I try using c.Address + 3 but it can't work.
Any help will be appreciate!
Thanks!
Private Sub Worksheet_SelectionChange(ByVal Target As Range)
For Each c In Worksheets("Sheet1").Range("A1:C1").Cells
If c.Interior.Color = 255 Then
Sheet1.Range(c.Address + 3 ).Interior.Color = 255 <<-- Can't work
Else
Sheet1.Range(c.Address + 3 ).Interior.Color = white <<-- Can't work
End If
Next c
End Sub

Answer 1

Change this:
Sheet1.Range(c.Address + 3 )
To this
Sheet1.Range(c.Address).offset(0,3)
Although I don't know why you need Sheet1.Range(c.Address) and not just c, is c a range? if so you can just do c.offset(0,3)

Answer 2

I really hoped, that Sixthsense is going to edit his answer so I can give him the +1 but it doesn't look like that will happen :(
Still knowing what he tried to achieve, I will at least show some working code and explain it a bit. So first things first: the code:
Option Explicit
Dim rngHolder As Range
Private Sub Worksheet_Activate()
If rngHolder Is Nothing Then Set rngHolder = Intersect(Selection, Range("A1:C1"))
End Sub
Private Sub Worksheet_SelectionChange(ByVal Target As Range)
If Not rngHolder Is Nothing Then
Dim rngRunner As Variant
For Each rngRunner In rngHolder.Cells
rngRunner.Offset(0, 3).Interior.Color = IIf(rngRunner.Interior.Color = 255, 255, xlNone)
Next
End If
Set rngHolder = Intersect(Target, Range("A1:C1"))
End Sub
The rngHolder (like the sPrev from Sixthsense) is important, because changing the selection, does not return the "old" selection. If you select A1 and change the color no trigger will be activated, so we are going with the Worksheet_SelectionChange. Now after the change, we select D19 and nothing will tell us that A1 has been changed. But we also do not want to run all changes every time the selection changes. For this reason the "last" selection will be stored inside the rngHolder.
I skipped some parts and directly push the selected ranges which cross the cells we need to look at in the variable (or nothing if no intersect is found).
If rngHolder is not empty the next time we select a different cell, it will run all cells in rngHolder to change the background color of the desired cells 3 columns to the right. (this way also changing multiple cells at once will work) and also push the new intersect in the rngHolder.
To the point which I was complaining about the solution of Sixthsense:
If the first selection you do is ...lets say X7... then selecting A3 afterwards will change the background color of AA7 to the same like X7 has. This may be not noticed due to conditional formatting and stuff like that. Wrong "highlight" however may leed to user-errors later on (you also may notice it at a point lots of cells have allready beed changed)
However, the question was just for the "Offset"-function which is already answered in a proper way ;)

Answer 3

Replace your current code with the below one.
Dim sPrev As String
Private Sub Worksheet_SelectionChange(ByVal Target As Range)
If sPrev = "" Then sPrev = Target.Address
If Target.Cells.Count = 1 Then
If Target.Column = Range("A:A").Column Then
With Range(sPrev)
.Offset(, 3).Interior.Color = .Interior.Color
End With
sPrev = Target.Address
End If
End If
End Sub