write:When using a variable we actually refer to an address of the memory where the data is stored. C language supports two kinds of variables.  Local variables  Global variables

arrays
and functions. They may consist of an alphabet
digit
or an underscore “ _ ” Rules for forming indentifier names  First letter must be an alaphabet White spaces are not allowed Uppercase letters are not allowed Key words not allowed Variables: variables is nothing but identifiers. A variable is defined as a meaningful name given to the data storage location in computer memory. When using a variable we actually refer to an address of the memory where the data is stored. C language supports two kinds of variables.  Local variables  Global variables Local variable: local variables are variables which are declared in its body. These life time and scope is valid in it‟s block only. Global variable: global variables are variables which are declared in out side body. These life time and scope is valid in through out programm. Example of Local Variable