vba help on declaring varible

[malleshg24]

Hi Team,

I am new in vba , learning it, I have a question, my below macro works give the result.
But if I write variable in between Parenthesis , my macro didn't work. like

Sub test(dim i as integer)

Below macro works.

Sub test()
Dim i As Long
For i = 1 To 10
    Range("a" & i).Value = i
Next i
End Sub

This didn't work.

Sub test(i As Long)

For i = 1 To 10
    Range("a" & i).Value = i
Next i
End Sub

On google I come across coding like as below?.... So which scenerio we have to declare
variable like the below One. Thanks in advance!

Sub QuickSort(coll As Collection, first As Long, last As Long