FLOOR(3M) FLOOR(3M)
NAME
fabs, floor, ceil, rint - absolute value, floor, ceiling, and round-to-nearest functions
SYNOPSIS
#include <math.h>
double floor(x)
double x;
double ceil(x)
double x;
double fabs(x)
double x;
double rint(x)
double x;
DESCRIPTION
Fabs returns the absolute value |x|.
Floor returns the largest integer no greater than x.
Ceil returns the smallest integer no less than x.
Rint returns the integer (represented as a double precision number) nearest x in the direction of the prevailing rounding mode.
NOTES
On a VAX, rint(x) is equivalent to adding half to the magnitude and then rounding towards zero.
In the default rounding mode, to nearest, on a machine that conforms to IEEE 754, rint(x) is the integer nearest x with the additional
stipulation that if |rint(x)-x|=1/2 then rint(x) is even. Other rounding modes can make rint act like floor, or like ceil, or round
towards zero.
Another way to obtain an integer near x is to declare (in C)
double x; int k; k = x;
Most C compilers round x towards 0 to get the integer k, but some do otherwise. If in doubt, use floor, ceil, or rint first, whichever you
intend. Also note that, if x is larger than k can accommodate, the value of k and the presence or absence of an integer overflow are hard
to predict.
SEE ALSO
abs(3), ieee(3M), math(3M)
4th Berkeley Distribution May 12, 1986 FLOOR(3M)