The gmp_neg() function is an in-built function in PHP which returns the negative of a GMP number (GNU Multiple Precision).
Syntax :
gmp_neg( $num )
Parameters : The function accepts only one mandatory parameter $num which can be either a GMP number resource in PHP 5.5 or a GMP object in PHP version 5.6 and later, or numeric strings can be passed to the function provided that it is possible to convert those strings to numbers.
Return Values : This function returns a GMP number (in PHP 5.5 and earlier) or a GMP object (in PHP 5.6 and later) which is negative of the value of $num.
Examples :
Input : $num = 255 Output : -255 Input : $num = 128 Output : -128
Below programs will illustrate the gmp_neg() function :
Program 1:
<?php //PHP program to illustrate //gmp_neg() function   $num = gmp_init("255");   $num1 = gmp_neg($num);   echo gmp_strval($num1); ?> |
Output:
-255
Program 2:
<?php //PHP program to illustrate //gmp_neg() function   $num = gmp_init("314567128");   $num1 = gmp_neg($num);   echo gmp_strval($num1); ?> |
Output:
-314567128
Reference : http://php.net/manual/en/function.gmp-neg.php
