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.