Arithmetic Operations On Characters

Arithmetic Operations On Characters

'C' allows us to manipulate characters in the same way we do with numbers.Whenever a character constant or character variable is used in an expression , it is automatically converted to integer value by the system .Integer value depends on local character set of the system .
     If the machine uses the ASCII representation then
                     x = 'a';
                     printf("%d", x);
 will display the number 97 on the screen.

ex: x = 'z'-1; is a valid statement
In ASCII , the value of 'z' is 122 , therefore the value
121 is assigned to x.
  The 'c' library supports a function that converts a string
of digits into their integer values .
   The function takes the form
         x = atoi(string);
     x is an integer variable and string is a character
array containing a string of digits.
ex:            ------------------
                 number = "1988";
                 year = atoi(number);
The function converts the string "1988" to its numeric
equivalent 1988 and assigns it to the integer variable year