C programming language was developed in 1972 by Dennis Ritchie at bell laboratories of AT&T (American Telephone & Telegraph), located in the U.S.A. Dennis Ritchie is known as the founder of the c language. It was developed to overcome the problems of previous languages such as B, BCPL, etc.
In a 16 Bit C compiler we have 2 bytes to store an integer, and 1 byte for a character. For unsigned integers the range is 0 to 65535. For signed integers the range is -32768 to 32767.
A compiler is a system software that converts high level language into machine level language.
The origin of C is closely tied to the development of the Unix operating system, originally implemented in assembly language on a PDP-7 by Dennis Ritchie and Ken Thompson, incorporating several ideas from colleagues.
main is a function not a keyword
The first character of an identifier can only contain alphabet(a-z , A-Z) or underscore ( _ ).
No special characters, such as semicolon, period, whitespaces, slash or comma are permitted to be used in or as Identifier.