strtod()                 Convert String to Double
 
 #include   <stdlib.h>
 
 double     strtod(nptr,endptr);
 char       *nptr;                       Pointer to string
 char       **endptr;                    Pointer to end of scan
 
    strtod() converts a string to a double value.  The string is a
    sequence of characters that can be interpreted as a double value. The
    string must match this sequence:
 
        [whitespace] [sign] [digits] [.digits] [{d|D|e|E} [sign] digits]
 
    strtod() stops reading the string at the first character that cannot
    be recognized as part of a double value.  If 'endptr' is not NULL, it
    points to the character that stopped the scan.
 
    Returns:    The value of the floating-point number.  +/-HUGE is
                returned when the representation would cause an overflow
                or underflow. On error, ERRNO is set to ERANGE.
 
  -------------------------------- Example ---------------------------------
 
    The following statements convert two strings into doubles, add them
    together, and print the total.
 
           #include <stdlib.h>
           #include <stdio.h>
 
           double total;
           double dubl1, dubl2;
           char *str1 = "982.50 dollars", *str2 = "540.00 dollars";
           char *txt1, *txt2
           main()
           {
           /* The space before "dollars" will stop the scanning of string. */
               dubl1 = strtod(str1,&txt1);
               dubl2 = strtod(str2,&txt2);
               total = dubl1 + dubl2;
               printf("TOTAL: %.2f ",total);
            }

Seealso:


 strtol() 
 atof() 
 atol()