Scrie o funcție în PHP 7+ care să verifice un număr natural.

CheckIfIsNumber.php

<?php
/**
 * Created by PhpStorm.
 * User: cosmi
 * Date: 09-Apr-18
 * Time: 7:57 AM
 */


function CheckIfIsNumber($number = null){
    if($number === (object)$number)
        return false;
    if ($number <= 0)
        return false;
    if($number >= 9876543210)
        return false;
    if ($number === (int)$number)
        return true;
}
echo(assert(CheckIfIsNumber(42)));
echo(assert(CheckIfIsNumber("42")));
echo(assert(CheckIfIsNumber(0)));
echo(assert(CheckIfIsNumber(-1)));
echo(assert(CheckIfIsNumber(new stdClass())));
echo(assert(CheckIfIsNumber(111454013352)));
echo(assert(CheckIfIsNumber(123)));
echo(assert(CheckIfIsNumber(0111454013352)));
echo(assert(CheckIfIsNumber("42aaa")));
echo(assert(CheckIfIsNumber("4a2b")));
echo(assert(CheckIfIsNumber(1.2)));
echo(assert(CheckIfIsNumber(null)));
echo(CheckIfIsNumber((object)['caught' => true]));
echo(assert(CheckIfIsNumber((object)['caught' => true])));
echo(assert(CheckIfIsNumber('-2.0')));
echo(assert(CheckIfIsNumber(2.0)));
echo(assert(CheckIfIsNumber(array(42))));
echo(assert(CheckIfIsNumber(99999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999)));
echo(assert(CheckIfIsNumber(0.9999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999)));
echo(assert(CheckIfIsNumber(2)));
echo(assert(CheckIfIsNumber('b')));
echo(assert(CheckIfIsNumber("x100")));
echo(assert(CheckIfIsNumber((int)b'111')));

https://devforum.ro/t/scrie-o-functie-in-php-7-care-sa-verifice-un-numar-natural/7479