'210010106140040100' == '210010106140040101'


Posted on 16th Feb 2014 07:03 pm by admin

Debugging this simple line of a PHP script

Code: if($a == $b){ }
I've found that with value of
Did you know?Explore Trending and Topic pages for more stories like this.
$a = '210010106140040100' (type = string)
$b = '210010106140040101' (type = string)

the result of the comparison is TRUE

the same if i compare 2 integer

$a = 210010106140040100 (type = int)
$b = 210010106140040101 (type = int)

$a == $b ( true )

If I use the === operator

'210010106140040100' === '210010106140040101' (comparison of strings: result is FALSE)
210010106140040100 === 210010106140040101 (comparison of numbers: result is TRUE)

I think it could be caused by the fact that the string is 'like' integer, but exceed the standard size of integer number.
But the final result remain a mistery for me: I've tested some others 'big' numbers and I've found for example:

18014398509481980==18014398509481981 (true) !!!!
18014398509481982==18014398509481981 (false) !!!!

In my specific script i can handle this specific comparison using the === operator, because i can assume that the variable are string.

But i'd like to know why this happen, and i'd appreciate suggestions about how to efficiently compare 'big' integers.

Thanks!

I use PHP 5.2 with IIS
No comments posted yet

Your Answer:

Login to answer
199 Like 53 Dislike
Previous forums Next forums
Other forums

big pagination problem in php
<?php

$connect = mysql_connect("localhost", "root", "")

URL Rewrite issue
Im created a series of Rewrites and on page checks to make sure the correct url is being called. But

isset undefined variable
Hi all,

Hope someone can point out the obvious. I've a log in script, if you dont enter a use

upload photo limits
ive got a upload photo script and im just trying to make more secure currently it limits size and as

Is there a function ... auto send IP
Is there some function that can be sent to a ddns service that returns the ip address of a ddns forw

Changes to hosting company's server has affected web contact form
I started a thread a couple of months ago about the contact forms on my client's website. Basically

MYSQL gen help
This is my Mysql gen. can anyone tell me why this echos

MID(networkset.networkid, 3, 3) AS &q

Why do I get this error
Parse error: syntax error, unexpected T_STRING, expecting ',' or ';' in /home/a5488351/public_html/b

line breaks in between fetched file names
Hi,

I have this code:
Code: <?php
if($dir = opendir('files')){
while (($f

Security Exception on pages using AJAX
I am getting the exception: attempted to perform an operation not allowed by the security policy on

Sign up to write
Sign up now if you have flare of writing..
Login   |   Register
Follow Us
Indyaspeak @ Facebook Indyaspeak @ Twitter Indyaspeak @ Pinterest RSS



Play Free Quiz and Win Cash