bcmod

(PHP 4, PHP 5, PHP 7)

bcmod — Get modulus of an arbitrary precision number

Description

string bcmod ( string $left_operand , string $modulus )

Get the modulus of the left_operand using modulus.

Parameters

left_operand: The left operand, as a string.
modulus: The modulus, as a string.

Return Values

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

Examples

Example #1 bcmod() example


<?php
echo bcmod('4', '2'); // 0
echo bcmod('2', '4'); // 2
?>

User Contributed Notes

drahoszdenek at gmail dot com

3 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
?>

lauris at night dot lt

12 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 );

?>

sebas at stageprikbord dot nl

9 years ago


function bc_is_even($int_str) {
  return (int)!($int_str & 1);
}

More resource efficient version of 'bc_is_even'.

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