• The first character of the identifier must be a letter of the alphabet (upper or lowercase) or an underscore ('_').
• The rest of the identifier name can consist of letters (upper or lowercase), underscores ('_') or digits (0-9).
• Identifier names are case-sensitive. For example,myname andmyName are not the same. Note the lowercasen in the former and the uppercaseN in te latter.
• Examples of valid identifier names arei,__my_name,name_23 anda1b2_c3.