GMP
PHP Manual

gmp_popcount

(PHP 4 >= 4.0.4, PHP 5)

gmp_popcount — Population count

说明

int gmp_popcount ( resource $a )

Get the population count.

参数

a

It can be either a GMP number resource, or a numeric string given that it is possible to convert the latter to a number.

返回值

The population count of a , as an integer.

范例

Example#1 gmp_popcount() example

<?php
$pop1 
gmp_init("10000101"2); // 3 1's
echo gmp_popcount($pop1) . "\n";
$pop2 gmp_init("11111110"2); // 7 1's
echo gmp_popcount($pop2) . "\n";
?>

上例将输出:

3
7


GMP
PHP Manual