C Keywords and Identifier

Character set Of C

Alphabets:

Uppercase: A ,B ,C .................................... X ,Y ,Z

Lowercase: a, b, c ...................................... x, y ,z

Digits: 0,1, 2 ,3, 4 ,5, 6,  8 ,9

Special Symbols: ~ ! @ # $ % ^ & * ( ) - _ = + | \ { } [ ] : ; " ' < > , . ?

Keywords

Keywords are the reserved words used in programming. Each keywords has fixed meaning and that cannot be changed by user. For example: int x;

Here, int is a keyword (integer) that indicates, 'x' as a type of integer.

Note: C programming is case sensitive, all keywords must be written in lowercase predefined by ASCII C.
             Keywords in C Language are : auto ,double ,int ,struct ,break ,else ,long ,switch ,case                                                                     ,enum ,register ,  type , def ,char ,extern ,return                                                                               ,union ,continue ,for ,signed ,void ,do ,if ,static ,while                                                                         ,default ,goto ,sizeof volatile ,const ,float ,short                                                                                   ,unsigned

Identifiers

In C programming, identifiers are names given to C entities, such as variables, functions, structures etc. Identifier are created to give unique name to C entities to identify it during the execution of program. For example:int x; int student_age;


Here, x is a identifier which represents a variable of type integer. Similarly, student-age is another identifier, which represents another variable of type integer.

Note :- Max. length of  identifier is 8 characters with no numeric and symbols started by.