bcmod

(PHP 4, PHP 5, PHP 7, PHP 8)

bcmod — Get modulus of an arbitrary precision number

Description

bcmod(string $num1, string $num2, ?int $scale = null): string

Get the remainder of dividing num1 by num2. Unless num2 is zero, the result has the same sign as num1.

Parameters

num1: The dividend, as a string.
num2: The divisor, as a string.
scale: This optional parameter is used to set the number of digits after the decimal place in the result. If omitted, it will default to the scale set globally with the bcscale() function, or fallback to 0 if this has not been set.

Return Values

Returns the modulus as a string.

Errors/Exceptions

This function throws a ValueError in the following cases:

num1 or num2 is not a well-formed BCMath numeric string
scale is outside the valid range

This function throws a DivisionByZeroError exception if num2 is 0.

Changelog

Version	Description
8.0.0	`scale` is now nullable.
8.0.0	Dividing by 0 now throws a DivisionByZeroError exception instead of returning null.
7.2.0	`num1` and `num2` 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
?>

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User Contributed Notes 2 notes

down

lauris at night dot lt ¶

20 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 );

?>