Answer 1

M.MANIVANNAN

Clrscr() It is a predefined function in "conio.h" (console input output header file) used to clear the console screen. Using of clrscr() is always optional but it should be place after variable orfunction declaration only.

source:
https://www.sitesbay.com/cpp/cpp-clrscr()-and-getch()

delline()function deletes the line containing the cursor and move all lines below it one line up.

source:
https://www.programmingsimplified.com/c/conio.h/delline

others useful link: https://www.includehelp.com/c-programs/clrscr-and-delline-functions-of-conio-h.aspx

I hope I was helpful