Each words used in c programming to identify the name of variables, functions, arrays, pointers and symbolic constants are known as identifiers.
They are name given by the user consisting a sequence of letters, digits and underscores.
Rules for naming identifiers:
- It must be a combination of letters and digits or letters only.
- It must begin with letter not by a digit.
- Underscore can put between two words, but white space is not allowed.
- Only first 31 characters are significant (i.e. shouldn’t longer that 31 characters).
- Keywords can’t be used.
- It is case sensitive (i.e. uppercase and lowercase are different).