PHP | gmp_cmp() Function

The gmp_cmp() is an inbuilt function in PHP which is used to compare two GMP numbers(GNU Multiple Precision : For large numbers).

Syntax:

gmp_cmp($num1, $num2)

Parameters: This function accepts two GMP numbers $num1 and $num2 as mandatory parameters as shown in the above syntax for comparing. These parameters can be a GMP object in PHP version 5.6 and later, or we are also allowed to pass numeric strings such that it is possible to convert those strings in numbers.

Return Value: The function returns “1” if $num1 > $num2, “0” if $num1 equal to $num2, “-1” if $num1 < $num2.

Examples:

Input : gmp_cmp("1234", "1236")
Output : -1

Input : gmp_cmp("3569", "3569")
Output : 0

Below programs illustrate the gmp_cmp() function in PHP:

Program 1: Program to compare the two GMP numbers when they are passed as numeric strings.

<?php
// PHP program to compare two
// GMP numbers passed as arguments

// strings as GMP numbers
$num1 = "12356";
$num2 = "12356";

// compares the two numbers and
// gives the result "0" as both are equal
$res = gmp_cmp($num1, $num2);

echo $res;

?>

Output:

0

Program 2: Program to compare two GMP numbers when they are passed as GMP numbers as arguments.

<?php

// PHP program to compare two
// GMP numbers passed as arguments

// creating GMP numbers using gmp_init()
$num1 = gmp_init(12355);
$num2 = gmp_init(12356);

// compares these two numbers and
// gives the result "-1" as $num1 < $num2
$res = gmp_cmp($num1, $num2);

echo $res;
?>

Output:

-1

Reference:
http://php.net/manual/en/function.gmp-cmp.php