bcdiv

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

bcdiv — Divide two arbitrary precision numbers

Description

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

Divides the num1 by the num2.

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 result of the division as a string, or null if num2 is 0.

Changelog

Version	Description
8.0.0	`scale` is now nullable.

Examples

Example #1 bcdiv() example

<?php

echo bcdiv('105', '6.55957', 3);  // 16.007

?>

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User Contributed Notes 1 note

down

MM ¶

16 years ago

Perhaps some one can find useful this function to compute the modular inverse of a integer (extended euclidean algorithm):

  function invmod($a,$b) {
    $n=$b;
    $x=0; $lx=1; $y=1; $ly=0;
    while ($b) {
      $t=$b;
      $q=bcdiv($a,$b,0);
      $b=bcmod($a,$b);
      $a=$t;
      $t=$x; $x=bcsub($lx,bcmod(bcmul($q,$x),$n)); $lx=$t;
      $t=$y; $y=bcsub($ly,bcmod(bcmul($q,$y),$n)); $ly=$t;
    }
    if (bccomp($lx,0) == -1)
      $lx=bcadd($lx,$n);
    return $lx;
  }

  // verify

  $n="2447995268898324993537772139997802321";
  $t="64941057316178801556773346239351236811";
  $m="123456789";
  $i=invmod($t,$n);
  // (t*m)*inv(t) is m
  echo bcmod(bcmul(bcmod(bcmul($t,$m),$n),$i),$n) == $m;