Identifier: A Program Element

 Data items of a Computer Program are recognized with the help of Identifiers. Identifiers serve to identify data items. Programming requires use of Identifiers. We can associate Identifiers with digits, alphabets, alphanumeric strings, and boolean values.

RULES FOR IDENTIFIER FORMATION:

( 1 ) Composition of Identifiers:

Only alphabet(s), underscore(s), or digit(s) can come together to form Identifiers.

 ( 2 ) First Occurence Particulars: 

An Identifier is declared to be invalid if a digit occurs in the Identifier at the first place. Either an alphabet , or an underscore (_) can be the occupant of the first place of a well-formed Identifier. One must be careful about the placement of digit(s).

( 3 ) Case Sensitivity Matters: 

Uppercase and lowercase letters have a distinct identity. 'N' and 'n' are altogether different. 'R' and 'r' are treated differently from each other.

( 4 ) Impermissible White spaces: White space inclusion anywhere in an identifier is to be checked. Care must be taken.

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Examples of Valid Identifiers:

( A ) x

( B ) found

( C ) BCD2

( D ) a

( E ) _temp

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Advantages of Using Identifiers:

( 1 ) Understandability: Data Items become understandable. One can easily tell that the Identifier 'x' is generally for a number. Similarly we can easily say that 'found' is for a boolean(decision).

( 2 ) Readability: Readability of a Computer Program gets improved if a Programmer selects intelligible names for identifiers. 

( 3 ) Qualitative Improvement: Identifiers impact Software Quality. The goodness of a Computer Program that is based on reasonable naming of Identifiers is felt by everyone.

( 4 ) Simplification: Identifiers serve to simplify Computer Programs. Wise decisions related to  identifiers march to make our Computer Programs understandable. Identifier Issues such as width, composition, and sometimes  that resounding punch really helps.

( 5 ) Tracing: Purposeful Identifiers make it easy to trace the details of data processing. The task of tracing the processing activities is facilitated.

( 6 ) Distinctiveness: Identifiers make the appearance of a Computer Program distinct. A Computer Program based on mathematical principles appears different. An Inventory Management  Program looks distinct. Identifiers are responsible for such distinctiveness.