C Identifiers

Identifiers are names given to different names given to entities such as constants, variables, structures, functions etc.

Example:
int amount;

double totalbalance;

In the above example, amount and totalbalance are identifiers and int, and double are keywords.

Rules for Naming Identifiers

  • An identifier can only have alphanumeric characters (a-z , A-Z , 0-9) (i.e. letters & digits) and underscore( _ ) symbol.
  • Identifier names must be unique
  • The first character must be an alphabet or underscore.
  • You cannot use a keyword as identifiers.
  • Only first thirty-one (31) characters are significant.
  • Must not contain white spaces.
  • Identifiers are case-sensitive.