Identifier :

The Identifiers are the names used to represent variable, constants, types, functions and labels in the program. Identifier is an important feature of all computer languages. A good identifier name should be descriptive but short.  

An Identifier in C++ may consist of 31 characters. If the name of an identifier is longer than 31 characters, the first character will be used. The remaining characters will be ignored by C++ compiler.

 Some important rules for identifier name are as follows :

• The first character must be an alphabetic or underscore ( _ ).
• The identifier name must consist of only alphabetic characters, digits or underscores.
• The reserved word cannot be used as identifier name.

Types of Identifier :

C++ provides the following types of identifiers :

1. Standard Identifier :

                                       A type of identifier that has special meaning in C++ is known as standard identifier. 

Example :

            cout and cin examples of standard identifiers.

    2.   User-defined Identifiers :

                                                         The type of identifier that is defined by the programmer
 to access memory location is known as user-defined identifiers.

Example :

               Some examples of user-defined identifiers are a, marks and age etc.