Hai…
Try this way…
Column_Count = DataTable_Variable.columns.count
Column_Count = Column_Count -1
In assign create variable to store that alphabet
chr(65 + column_Count)
For ex,
If your column count is 4 means
Its going to degrees one , so its 3
Now, 3 is your existing final column index
When we use chr(65+column_count)
Chr(65+3) output is D
Now your last existing column is D
Then you can add column_count + 1… You get next column of E to write your next data