{"id":11959,"date":"2023-01-27T07:45:33","date_gmt":"2023-01-27T07:45:33","guid":{"rendered":"https:\/\/www.prepbytes.com\/blog\/?p=11959"},"modified":"2023-08-18T07:14:08","modified_gmt":"2023-08-18T07:14:08","slug":"keywords-and-identifiers-in-c-language","status":"publish","type":"post","link":"https:\/\/prepbytes.com\/blog\/keywords-and-identifiers-in-c-language\/","title":{"rendered":"Keywords & Identifiers in C Language"},"content":{"rendered":"

\"\"<\/p>\n

Within this article, we shall delve into the realm of keywords and identifiers in C language. To put it plainly, keywords represent distinctive, predefined terms with meanings already recognized by the compiler. On the other hand, identifiers play a pivotal role in labeling variables, functions, and arrays. They serve as the means to distinctly designate a particular variable’s name.<\/p>\n

What are Keywords in C<\/h2>\n

These words have special meanings and we cannot use these words elsewhere in the program This word is used in a specific condition and it specifies the type of some particular variable? No special symbol can be used keywords have standard predefined meanings. Keywords are also known as reserved words and we cannot alter the meaning of keywords. Keywords are the basic building blocks for developing C programs.<\/p>\n

All Keywords in C<\/h3>\n

There are only 32 keywords in standard C and these keywords must be written in lowercase.
\nAll keywords in c are following<\/p>\n

   auto    break     case     char     const     continue\n   default     do     double     else     enum     extern\n   float     for     goto     if     int     long\n   register     return     short     signed     static\n   struct     switch     typedef     union     unsigned     void\n   volatile     while<\/code><\/pre>\n
Identifiers<\/h2>\n
These are user-defined names used for naming of variables, function and arrays
\nWe  cannot  use keyword as identifiers. Identifiers must be different from the keywords because we have studied earlier that keywords are reserved words
\nThat have predefined meanings. Identifiers are simple text or strings to identify various identities. An identifier can consist of alphabetical digits characters and underscores. The first character can be an uppercase, lowercase letter, or underscore.<\/p>\n
Rules for Naming Identifiers in C<\/h3>\n
    \n
  • Identifier should not be a keyword<\/li>\n
  • Identifiers can not start with a digit.<\/li>\n
  • All the identifiers should have a unique name in the same scope<\/li>\n
  • The first character of an identifier should always start with an alphabet or underscore, and then it can be followed by any of the characters, digit, or underscore.<\/li>\n
  • The special characters such as ‘*’,’#’,’@’,’$’ are not allowed within an identifier.<\/li>\n
  • All the identifiers are case sensitive means the identifiers "hello" and "Hello" will be treated differently. However, both names are identical, but one has a lowercase alphabet, and the other has an uppercase alphabet.<\/li>\n
  • Length of an identifier should not exceed 31 characters.<\/li>\n
  • Any blank spaces or commas are not allowed within an identifier.<\/li>\n<\/ul>\n
    Types of Identifiers in C<\/h3>\n
    There are two types of identifiers in C language <\/strong><\/p>\n
    1. Internal Identifier<\/strong>
    \nThese are also known as internal names which includes the names of local variables. Internal
    \nIdentifier can be a local variable that has 31 significant characters.<\/p>\n
    2. External Identifier<\/strong>
    \nThese identifiers are used in the external link process (process refers to a whole program that combines all the translation units(implemented file + all header files ). External identifiers are also known as external names .it can be a name of a function or a  global variable. it has at least 63 significant characters.<\/p>\n
    Difference between Keywords and Identifiers<\/h2>\n\n\n\n\n\n\n\n\n\n
    \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 Keyword<\/th>\n\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 Identifiers<\/th>\n<\/tr>\n<\/thead>\n
    These are special specific, reserved words that have special meanings and we cannot use these words elsewhere in the program<\/td>\nIdentifiers are simple text or strings to identify various identities. An identifier can consist of alphabetical digits characters and underscores.<\/td>\n<\/tr>\n
    The keyword specifies the variable type<\/td>\nIdentifier specifies the name of the variable<\/td>\n<\/tr>\n
    No special symbol can be used because these are not user-defined.<\/td>\nA special symbol Underscore can be used\u00a0<\/td>\n<\/tr>\n
    Keyword in c always consists of lowercase\u00a0 alphabets and starts with lower case<\/td>\nIdentifier can be both uppercase and lowercase, and it can start with the alphabet or underscore.<\/td>\n<\/tr>\n
    Example-:for, float, int, while, do, class, etc.<\/td>\nExample -: Vikas, name,school_no, etc.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n
    Code Implementation<\/strong>
    \n\t\t\t\t\t\t