Category : C Source Code
Archive   : CEPHES22.ZIP
Filename : ROUND.C

 
Output of file : ROUND.C contained in archive : CEPHES22.ZIP
/* round.c
*
* Round double to nearest or even integer valued double
*
*
*
* SYNOPSIS:
*
* double x, y, round();
*
* y = round(x);
*
*
*
* DESCRIPTION:
*
* Returns the nearest integer to x as a double precision
* floating point result. If x ends in 0.5 exactly, the
* nearest even integer is chosen.
*
*
*
* ACCURACY:
*
* If x is greater than 1/(2*MACHEP), its closest machine
* representation is already an integer, so rounding does
* not change it.
*/

/*
Cephes Math Library Release 2.1: January, 1989
Copyright 1984, 1987, 1989 by Stephen L. Moshier
Direct inquiries to 30 Frost Street, Cambridge, MA 02140
*/


double round(x)
double x;
{
double y, r;
double floor();

/* Largest integer <= x */
y = floor(x);

/* Fractional part */
r = x - y;

/* Round up to nearest. */
if( r > 0.5 )
goto rndup;

/* Round to even */
if( r == 0.5 )
{
r = y - 2.0 * floor( 0.5 * y );
if( r == 1.0 )
{
rndup:
y += 1.0;
}
}

/* Else round down. */
return(y);
}


  3 Responses to “Category : C Source Code
Archive   : CEPHES22.ZIP
Filename : ROUND.C

  1. Very nice! Thank you for this wonderful archive. I wonder why I found it only now. Long live the BBS file archives!

  2. This is so awesome! 😀 I’d be cool if you could download an entire archive of this at once, though.

  3. But one thing that puzzles me is the “mtswslnkmcjklsdlsbdmMICROSOFT” string. There is an article about it here. It is definitely worth a read: http://www.os2museum.com/wp/mtswslnk/