gmp_sign

(PHP 4 >= 4.0.4, PHP 5, PHP 7)

gmp_sign — Sign of number

gmp_sign ( GMP $a ) : int

Checks the sign of a number.

a: Either a GMP number resource in PHP 5.5 and earlier, a GMP object in PHP 5.6 and later, or a numeric string provided that it is possible to convert the latter to an integer.

Returns 1 if a is positive, -1 if a is negative, and 0 if a is zero.

Example #1 gmp_sign() example


<?php
// positive
echo gmp_sign("500") . "\n";

// negative
echo gmp_sign("-500") . "\n";

// zero
echo gmp_sign("0") . "\n";
?>

以上例程会输出：

1
-1
0