note 80939 added to function.round
| From: | altsoph at osu1 dot php dot net | Date: | Thu, 07 Feb 2008 18:30:08 +0000 |
| Subject: | note 80939 added to function.round | ||
| Groups: | php.notes | ||
| Request: | Send a blank email to php-notes+get-135875@lists.php.net to get a copy of this message | ||
Another way to code all 7 rounding methods according IEEE754 standart:
<?php
// We need precision parameter for ceil & floor
function p_ceil( $val, $d )
{
return ceil($val * pow (10, $d) )/ pow (10, $d) ;
}
function p_floor( $val, $d )
{
return floor($val * pow (10, $d) )/ pow (10, $d) ;
}
// We need signum
function sgn($x)
{
return $x ? ($x>0 ? 1 : -1) : 0;
}
// Now seven functions for standart rounding methods
function round_down($num, $d = 0)
{
return sgn($num)*p_floor(abs($num), $d);
}
function round_up($num, $d = 0)
{
return sgn($num)*p_ceil(abs($num), $d);
}
function round_half_even($num, $d = 0)
{
if( round($num,$d) == round_half_down($num,$d) )
return round($num,$d);
$pre_digit = round_down( $num, $d );
if( ($pre_digit/2) == round_down($pre_digit/2,$d) )
return round_down($num, $d);
else
return round_up($num, $d);
}
function round_ceiling($num, $d = 0)
{
return p_ceil($num, $d);
}
function round_floor($num, $d = 0)
{
return p_floor($num, $d);
}
function round_half_down($num, $d = 0)
{
return ((2*round_up($num,$d)==round_up(2*$num,$d))
? round($num,$d) : round_down($num,$d) );
}
function round_half_up($num, $d = 0)
{
return round($num, $d);
}
?>
My article (in Russian) about rounding in PHP is here:
http://altsoph.ru/?p=521
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----
Manual Page -- http://www.php.net/manual/en/function.round.php
Edit -- https://master.php.net/note/edit/80939
Del: integrated -- https://master.php.net/note/delete/80939/integrated
Del: useless -- https://master.php.net/note/delete/80939/useless
Del: bad code -- https://master.php.net/note/delete/80939/bad+code
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Del: non-english -- https://master.php.net/note/delete/80939/non-english
Del: in docs -- https://master.php.net/note/delete/80939/in+docs
Del: other reasons-- https://master.php.net/note/delete/80939
Reject -- https://master.php.net/note/reject/80939
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