bcmod

(PHP 4, PHP 5, PHP 7)

bcmodGet modulus of an arbitrary precision number

Description

string bcmod ( string $dividend , string $divisor [, int $scale ] )

Get the remainder of dividing dividend by divisor. Unless divisor is zero, the result has the same sign as dividend.

Parameters

dividend

The dividend, as a string.

divisor

The divisor, as a string.

Return Values

Returns the modulus as a string, or NULL if divisor is 0.

Changelog

Version Description
7.2.0 dividend and divisor are no longer truncated to integer, so now the behavior of bcmod() follows fmod() rather than the % operator.
7.2.0 The scale parameter was added.

Examples

Example #1 bcmod() example

<?php
bcscale
(0);
echo 
bcmod'5',  '3'); //  2
echo bcmod'5''-3'); //  2
echo bcmod('-5',  '3'); // -2
echo bcmod('-5''-3'); // -2
?>

Example #2 bcmod() with decimals

<?php
bcscale
(1);
echo 
bcmod('5.7''1.3'); // 0.5 as of PHP 7.2.0; 0 previously
?>

See Also

  • bcdiv() - Divide two arbitrary precision numbers

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User Contributed Notes 2 notes

up
3
lauris at night dot lt
14 years ago
<?php
/**
* my_bcmod - get modulus (substitute for bcmod)
* string my_bcmod ( string left_operand, int modulus )
* left_operand can be really big, but be carefull with modulus :(
* by Andrius Baranauskas and Laurynas Butkus :) Vilnius, Lithuania
**/
function my_bcmod( $x, $y )
{
   
// how many numbers to take at once? carefull not to exceed (int)
   
$take = 5;    
   
$mod = '';

    do
    {
       
$a = (int)$mod.substr( $x, 0, $take );
       
$x = substr( $x, $take );
       
$mod = $a % $y;   
    }
    while (
strlen($x) );

    return (int)
$mod;
}

// example
echo my_bcmod( "7044060001970316212900", 150 );
?>
up
2
drahoszdenek at gmail dot com
5 years ago
The modulus can be only integer. For "floats" bcmod returns 0:

<?php
echo bcmod('10', '2.1'); // 0
?>

For real modulus you can use BN-PHP project (hosted at Bitbucket):

<?php
$eval
= new \BN\Expression\ExpressionEvaluator();
$operators = new \BN\Expression\OperatorsFactory();
$eval->setOperators($operators->getOperators(array('%')));
       
echo
$eval->evaluate('10 % 2.1'); // 1.6
echo $eval->evaluate('10 % -2.1'); // 1.6
echo $eval->evaluate('-10 % 2.1'); // -1.6
echo $eval->evaluate('-10 % -2.1'); // -1.6
?>
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