atoi()                  Convert String to Integer

 #include <stdlib.h>

 int        atoi(string);                The integer value of string
 const char *string;                     String to be converted

    atoi() converts 'string' to an integer value.  atoi() does not
    recognize decimal points or exponents.  'string' has the following
    format:

                [whitespace][sign]digits
     where:

            whitespace       any number of tab or space characters
                             are ignored
            sign             + or -
            digits           one or more decimal digits

       Returns:     The integer value of 'string'.  If 'string' cannot be
                    converted to an integer, 0 is returned.  The return
                    value is undefined for overflow.

   -------------------------------- Example ---------------------------------

    The following statements convert a string to an integer and print the
    result.

           #include <stdlib.h>

           char   *s;
           int    i;

           main()
           {
               s = "12345";
               i = atoi(s);
               printf("%d\n",i);
           }