C – Identifiers

C – Identifiers 2017-08-05T14:05:23+00:00

Identifiers :

Identifiers are the names that are given to various program elements such as variables, symbolic constants and functions.Variable or function identifier that is called a symbolic constant name.

Identifier can be freely named, the following restrictions.

    • Alphanumeric characters ( a ~ z , A~Z , 0~9 ) and half underscore ( _ ) can only be used.
    • The first character of the first contain letters ( a ~ z , A~Z ) or half underscore ( _ ) can only be used.
    • Case is distinguishable. That is, word and WORD is recognized as a separate identifier.
    • Reserved words are not allowed. However, part of an identifier reserved words can be included.

Here are the rules you need to know:

  •        Identifier name must be a sequence of letter and digits, and must begin with a letter.
  •        The underscore character (‘_’) is considered as letter.
  •        Names shouldn’t be a keyword (such as int , float, if ,break, for etc)
  •        Both upper-case letter and lower-case letter characters are allowed. However, they’re not interchangeable.
  •        No identifier may be keyword.
  •        No special characters, such as semicolon,period,blank space, slash or comma are permitted

Examples of legal and illegal identifiers follow, first some legal identifiers:

float _number;

float a;

int this_is_a_very_detailed_name_for_an_identifier;

The following are illegal (it’s your job to recognize why):

float :e;

float for;

float 9PI;

float .3.14;

float 7g;


Output :

Enter two Numbers



Sum of 10 and 20 is 30

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