bcpowmod

(PHP 5, PHP 7)

bcpowmodRaise an arbitrary precision number to another, reduced by a specified modulus

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bcpowmod ( string $base , string $exponent , string $modulus [, int $scale = 0 ] ) : string

Use the fast-exponentiation method to raise base to the power exponent with respect to the modulus modulus.

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base

The base, as an integral string (i.e. the scale has to be zero).

exponent

The exponent, as an non-negative, integral string (i.e. the scale has to be zero).

modulus

The modulus, as an integral string (i.e. the scale has to be zero).

scale

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

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Note:

Because this method uses the modulus operation, numbers which are not positive integers may give unexpected results.

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The following two statements are functionally identical. The bcpowmod() version however, executes in less time and can accept larger parameters.

<?php
$a 
bcpowmod($x$y$mod);

$b bcmod(bcpow($x$y), $mod);

// $a and $b are equal to each other.

?>

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  • bcpow() - ���⾫�����ֵij˷�
  • bcmod() - ��һ�����⾫������ȡģ