Not in C, only in TurboC.
Direct console input-output (MS-DOS specific).
just as you do it in C.
Their name, content and function.
Platform dependent, possibly LIBC.LIB or something like that.
You could, if you had conio.h in linux, but you don't have, that's why.
conio.h is a library function which is predefined in the header file and 'clrscr();','getch();' and many other functions come under this.
Console Input Output Header
Loads of them. Consult your help, or load these headers into a text-editor.
It is a letter and function it.
The main function defines the entry point of an application in C.
I don't use that function in C programme.
There is no such term as "building function" in C++.
The c language does not have template functions. That is a c++ thing.