PHP | gmp_scan1() Function (original) (raw)

Last Updated : 11 Jul, 2025

The gmp_scan1() is an inbuilt function which is used to scan "1" in the GMP number(GNU Multiple Precision : For large numbers) starting from given index which move towards most significant bits in the number.Syntax:

gmp_scan1($num, $index)

Parameters: This function accepts two parameters as explained below:

• $num: This parameter is a GMP number and is mandatory to be passed. This parameter can be a GMP object in PHP version 5.6 and later, or we are also allowed to pass a numeric string provided that it is possible to convert that string to a number.
• $index: This parameter represents the index or position in the bitwise representation of the number $num from where we want to start the search.

Return Value: The function returns the position where we find "1" in the number. Examples:

Input : gmp_scan1("101111101", 6) Output : 8

Input : gmp_scan1("111001111", 2) Output : 3

Below programs illustrate the gmp_scan1() function in PHP:Program 1: Program to find the position of "1" bit in GMP number when numeric strings as GMP numbers are passed as arguments.

php `

`

Output:

4

Program 2: Program to find the position of "1" bit in GMP number when GMP numbers are passed as arguments.

php `

`

Output:

3

Reference: https://www.php.net/manual/en/function.gmp-scan1.php