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bcpowmod
Podręcznik PHP
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bcpowmod

(PHP 5)

bcpowmod -- Raise an arbitrary precision number to another, reduced by a specified modulus

Opis

string bcpowmod ( string left_operand, string right_operand, string modulus [, int scale] )

Use the fast-exponentiation method to raise left_operand to the power right_operand with respect to the modulus modulus.

Parametry

left_operand

The left operand, as a string.

right_operand

The right operand, as a string.

modulus

The modulus, as a string.

scale

This optional parameter is used to set the number of digits after the decimal place in the result. You can also set the global default scale for all functions by using bcscale().

Zwracane wartości

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

Notatki

Notatka: Because this method uses the modulus operation, non-natural numbers may give unexpected results. A natural number is any positive non-zero integer.

Przykłady

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.

?>

Patrz także

bcpow()
bcmod()

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