I have 2 columns. Cloumn A has 1 to 100 column B some times has upto 50 rows
filled or sometimes upto 80 ans ometimes upto 100 rows filled.

When Column B is not completley filled how to fill the empty column with the
last entry in that column

for example 1.
cloumn B ends in row # 80 with a number 657 I want to fill the rest of the
rows in column B with 657 up to row #100.

for example 2.
cloumn B ends in row # 60 with a number 6257 I want to fill the rest of the
rows in column B with 6257 up to row #100.