Beginner VBA - Change Selection in Sample Uppercase Routine

Clint_E_Hill 

Sub Uppercase_selection()
Dim rng, x As Range
Set rng = Selection
   ' Loop to cycle through each cell in the specified range.
   For Each x In rng
   ' Change the text in the range to uppercase letters.
      x.Value = UCase(x.Value)
   Next
End Sub

With this code you can either select a cell or a range. Then run the code to change the selected cell or range to uppercase. I wouldn't run this code for the entire worksheet (17,178 billion cells) since it would run forever.