SAS/C Library Reference, Vol. 1

modf -- Floating-Point Conversion: Fraction-Integer Split

SYNOPSIS

 #include <math.h>

 double modf(double y, double *p);

DESCRIPTION

modf separates an argument of type double into fractional and integer parts.

RETURN VALUE

modf returns the fractional part of the argument y with the same sign as y. The integer part of y, expressed as a floating-point number, is stored in the location referenced by the pointer p.

IMPLEMENTATION

modf is implemented as a built-in function unless it is undefined by an #undef statement.

EXAMPLE

  #include <math.h>
  #include <stdio.h>

  main()
  {
     double weight;
     double intweight;
     float limit = 0.5;

     puts("Enter a weight");
     scanf("%lf",&weight);
        /* Check to see if weight is negative.                    */
     if (weight < 0) {
        puts("Weight can not be a negative number");
        exit(1);
     }

        /* Test whether fractional part equals or exceeds limit.  */
     if (modf(weight, &intweight) >= limit)
         weight = intweight + 1; /* If yes, add 1 to weight.      */
     else
         weight = intweight;     /* Otherwise, round down weight. */
     printf("Your weight rounded off to the nearest pound is %fn",
            weight);
  }

RELATED FUNCTIONS

ceil, floor, fmod