/*

* FUNCTION

* <<div>>---divide two integers

* INDEX

* div

* ANSI_SYNOPSIS

* #include <stdlib.h>

* div_t div(int <[n]>, int <[d]>);

* TRAD_SYNOPSIS

* #include <stdlib.h>

* div_t div(<[n]>, <[d]>)

* int <[n]>, <[d]>;

* Divide

* @tex

* $n/d$,

* @end tex

* @ifinfo

* <[n]>/<[d]>,

* @end ifinfo

* returning quotient and remainder as two integers in a structure <<div_t>>.

* RETURNS

* The result is represented with the structure

* . typedef struct

* .  int quot;

* .  int rem;

* . } div_t;

* where the <<quot>> field represents the quotient, and <<rem>> the

* remainder.  For nonzero <[d]>, if `<<<[r]> = div(<[n]>,<[d]>);>>' then

* <[n]> equals `<<<[r]>.rem + <[d]>*<[r]>.quot>>'.

* To divide <<long>> rather than <<int>> values, use the similar

* function <<ldiv>>.

* PORTABILITY

* <<div>> is ANSI.

* No supporting OS subroutines are required.

* 

*

*/

/*

 * Copyright (c) 1990 Regents of the University of California.

 * All rights reserved.

 *

 * This code is derived from software contributed to Berkeley by

 * Chris Torek.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 * 1. Redistributions of source code must retain the above copyright

 *    notice, this list of conditions and the following disclaimer.

 * 2. Redistributions in binary form must reproduce the above copyright

 *    notice, this list of conditions and the following disclaimer in the

 *    documentation and/or other materials provided with the distribution.

 * 3. All advertising materials mentioning features or use of this software

 *    must display the following acknowledgement:

 *	This product includes software developed by the University of

 *	California, Berkeley and its contributors.

 * 4. Neither the name of the University nor the names of its contributors

 *    may be used to endorse or promote products derived from this software

 *    without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND

 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE

 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL

 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS

 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)

 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT

 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY

 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF

 * SUCH DAMAGE.

 */

#include <_ansi.h>

#include <stdlib.h>		/* div_t */

/**

Divide two integer values.

numer is divided by denom. 

Quotient and remainder are returned in a div_t structure.

@return   A div_t structure is returned

@param num Numerator. 

@param denom Denominator.

*/

EXPORT_C div_t div (int num, int denom)

{

	div_t r;

	r.quot = num / denom;

	r.rem = num % denom;

	/*

	 * The ANSI standard says that |r.quot| <= |n/d|, where

	 * n/d is to be computed in infinite precision.  In other

	 * words, we should always truncate the quotient towards

	 * 0, never -infinity.

	 *

	 * Machine division and remainer may work either way when

	 * one or both of n or d is negative.  If only one is

	 * negative and r.quot has been truncated towards -inf,

	 * r.rem will have the same sign as denom and the opposite

	 * sign of num; if both are negative and r.quot has been

	 * truncated towards -inf, r.rem will be positive (will

	 * have the opposite sign of num).  These are considered

	 * `wrong'.

	 *

	 * If both are num and denom are positive, r will always

	 * be positive.

	 *

	 * This all boils down to:

	 *	if num >= 0, but r.rem < 0, we got the wrong answer.

	 * In that case, to get the right answer, add 1 to r.quot and

	 * subtract denom from r.rem.

	 */

	if (num >= 0 && r.rem < 0) {

		r.quot++;

		r.rem -= denom;

	}

	return (r);

}