The identifier is the name for program elements (functions, variables, etc.) freely selected by the programmer:

  • The identifier must begin with a letter or underscore character;
  • Numbers can be used in the identifier along with the letters starting from the second position;
  • The characters input are case sensitive when specifying identifiers;
  • Space is a separator and can not be used inside the identifier;
  • Reserved words are not allowed as identifiers.