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Identifiers in C

Identifier define to name given to entities such as variables, functions, structures etc.

See in Example.

Here a and accountBalance is identifiers.

Here int is keyword

Rules for Identifiers

  • An identifier can have letters (both uppercase and lowercase letters), digits and underscores..
  • The first letter of an identifier should be either a letter or an underscore.
  • Commas or blank spaces cannot be specified within an identifier.
  • Keywords cannot be represented as an identifier.

Differences between Keyword and Identifier

Keyword Identifier
Keyword is a pre-defined word. The identifier is a user-defined word
It must be written in a lowercase letter. It can be written in both lowercase and uppercase letters.
Its meaning is pre-defined in the c compiler. Its meaning is not defined in the c compiler.
It is a combination of alphabetical characters. It is a combination of alphanumeric characters.
It does not contain the underscore character. It can contain the underscore character.



Value of a is : 5
Value of A is :10  
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