C Identifiers


Identifiers are sequences of characters used for naming variables, functions, new data types, and preprocessor macros. 


  • Identifier can be include letters uppercase(A-Z) and lowercase(a-z)
  • Identifier can be decimal digits(0-9). 
  • The first character of an identifier cannot be a digit. 
  • You Can Include underscore character ?_? in identifiers.The first character of an identifier cannot be an underscore(Some Compilers Accept underscore as a first Character). 
  • Lowercase letters and uppercase letters are distinct, such that foo and FOO are two different identifiers. 
  • When using GNU extensions, you can also include the dollar sign character ?$? in identifiers.


data_type name_of_identifeir // Variable name

data_type name_of_function(......)// function name

Identifiers Example

// Variable
int amount;
char name[20];

// Function
void calculation(int a,int b){