Answer:
For changing your username you can contact to administrator of the site. If you are using app then go to message option. Then search "rishilaugh" then you can message him. Hope it helps you!
Answer:
Your not including anything in your code.
Explanation:
According to your text all you have is #include. You didn't incldue any directives so you will get a error.
The answer would be A, ROM. CD-ROMs allow for easy software installation from a disk
Answer:
Napier's bones is a manually-operated calculating device created by John Napier of Merchiston, Scotland for the calculation of products and quotients of numbers. The method was based on lattice multiplication, and also called 'rabdology', a word invented by Napier.