PHP 5.4.33 Released

gmp_scan1

(PHP 4 >= 4.0.4, PHP 5)

gmp_scan1Scan for 1

说明

int gmp_scan1 ( GMP $a , int $start )

Scans a, starting with bit start, towards more significant bits, until the first set bit is found.

参数

a

The number to scan.

可以是一个 GMP 数据 resouce,或一个可以转换为数值的字符串。

start

The starting bit.

返回值

Returns the index of the found bit, as an integer. If no set bit is found, -1 is returned.

范例

Example #1 gmp_scan1() example

<?php
// "1" bit is found at position 3. index starts at 0
$s1 gmp_init("01000"2);
echo 
gmp_scan1($s10) . "\n";

// "1" bit is found at position 9. index starts at 5
$s2 gmp_init("01000001111"2);
echo 
gmp_scan1($s25) . "\n";
?>

以上例程会输出:

3
9

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