Php/docs/function.gmp-scan1
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gmp_scan1
(PHP 4 >= 4.0.4, PHP 5, PHP 7)
gmp_scan1 — Scan for 1
说明
gmp_scan1
( GMP $a
, int $start
) : int
Scans a
, starting with bit
start
, towards more significant bits,
until the first set bit is found.
参数
a
The number to scan.
PHP 5.5 之前为 GMP 数值资源,PHP 5.6 之后为 GMP 对象或数字,或可以转为数字的字符串。
start
The starting bit.
返回值
Returns the index of the found bit, as an int. If no set bit is found, -1 is returned.
范例
Example #1 gmp_scan1() example
<?php// "1" bit is found at position 3. index starts at 0$s1 = gmp_init("01000", 2);echo gmp_scan1($s1, 0) . "\n";// "1" bit is found at position 9. index starts at 5$s2 = gmp_init("01000001111", 2);echo gmp_scan1($s2, 5) . "\n";?>
以上例程会输出:
3 9