GMP
PHP Manual

gmp_sign

(PHP 4 >= 4.0.4, PHP 5)

gmp_sign — Sign of number

说明

int gmp_sign ( resource $a )

Checks the sign of a number.

参数

a

It can be either a GMP number resource, or a numeric string given that it is possible to convert the latter to a number.

返回值

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

范例

Example#1 gmp_sign() example

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

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

// zero
echo gmp_sign("0") . "\n";
?>

上例将输出:

1
-1
0


GMP
PHP Manual