Identifiers in C++ Programming Language

Identifiers are names given to variables, functions, arrays and other user defined structure. These are user defined names.

Steps (how to do):

1) Identifiers are formed with alphabets, digits and a special character underscore (-).
2) The first character must be an alphabet.
3) No special characters are allowed other than underscore.
4) They are case sensitive. That is AA is different from aa.
5) There is no limit for the number of characters.

Example:

1) The following are some valid identifiers
   A0, BASICPAY, basicpay, TOTAL_PAY, B12.
 
2) The following are invalid identifiers