Please help with macro (i'm a beginner)

Hello,
Please help me make a macro
I have a worksheet that looks like this:
on the row 2 0 0 0 1 0 0 0 3 0 0 0 0 0 0 3 0 0 0 8 0 0 0 1
and i want to copy cell contents to look like this
on the same row 2 2 2 2 1 1 1 1 3 3 3 3 3 3 3 3 3 8 8 8 8 1

it should sound like this
check the cell
if the cell is blank then copy contents from above (above i have some data)
if the cell is not blank then jump to next cell down and check to see if the cell is blank or not.
I hope i make my self clear
thank you