gmp_scan1
(PHP 4 >= 4.0.4, PHP 5)
gmp_scan1 — Scan for 1
說明
Scans a, starting with bit
start, towards more significant bits,
until the first set bit is found.
參數
-
a -
The number to scan.
可以是一個 GMP 數據 resouce，或一個可以轉換為數值的字串。
-
start -
The starting bit.
回傳值
Returns the index of the found bit, as an integer. If no set bit is found, -1 is returned.
範例
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";
?>
上例將輸出：
3 9
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