What is the difference between a function and a subroutine?

Question

What is the difference between a function and a subroutine? I was told that the difference between a function and a subroutine is as follows:

A function takes parameters

Answer 1

I am writing this answer from a VBA for excel perspective. If you are writing a function then you can use it as an expression i. e. you can call it from any cell in excel.

eg: normal vlookup function in excel cannot look up values > 256 characters. So I used this function:

Function MyVlookup(Lval As Range, c As Range, oset As Long) As Variant
  Dim cl As Range
  For Each cl In c.Columns(1).Cells
  If UCase(Lval) = UCase(cl) Then
  MyVlookup = cl.Offset(, oset - 1)
  Exit Function
  End If
  Next
End Function

This is not my code. Got it from another internet post. It works fine.

But the real advantage is I can now call it from any cell in excel. If wrote a subroutine I couldn't do that.