Question

Write about hex, oct and Dec manipulators?

Answer 1

hex used for 6
Oct used for 8
and DEC for 10

Answer 2

Manipulator are function   specifically  designed  to   used  in  conjunction  with the  insertion  and  extraction  and  operators  on the stream  object  for example  it can  count  boolalpha .

It is commonly used to  change formatting  parameters overt the stream  and also insert   certain  special characters.  

Hope this answer is right and provide  best  choice for the student