BlameThePixel!

BTForum » Main BTP Stuff » BlameTheGeneralDiscussion » PHP problem

Page: [1] []
[]Dingbats
;
Send PM
An Avatar
Posts: 1970
Threads: 50
Mood: Optative
Money: £268.57 (D)
(+ Friend)
Not online within the last half an hour
I'm trying to create a PHP script that checks whether a number is a prime number or not. Just because I'm bored. But I can't get it to work properly. This is what I've written:

\n
for($i = $_GET["number"]; $i <= ($_GET["number"] / 2); $i++) {
if(($_GET["number"] % $i) == 0) { $yes = true; break;
} } } ?> Prime number counter

Prime number counter





if(isset($_GET["number"])) { echo "Last number: "; if($yes)
{ echo "Prime number!"; } else { echo "Not a prime number."; } } ?>

Enter a number and press 'check'
to check if it is a prime number.

\n

I get no errors, but it's not working right. It says that all numbers above zero aren't prime numbers and that all numbers below or exact zero are prime numbers. What is wrong?
Edit: Yes, I have to write $_GET["number"] instead of $number, because of some weird setting somewhere.
08.03.04 15:06
Post #1		Last edited: 08.03.04 15:08 (Dingbats - 2 times) [Softbrain Games] [Hide Sig (2)] [Profile] [Quote]
[G]thor
Statusless
Send PM
Posts:
Threads:
Money: £0.00 (D)
(+ Friend)
Not online within the last half an hour
y'know when it says the form action is prime.php? shouldn't it be $PHP_SELF ?
08.03.04 16:06
Post #2		 [Hide Sig (0)] [Profile] [Quote]
[S]Zogger!
Looking For Status
Send PM
Posts: 3954
Threads: 62
Money: £93.82 (D)
(+ Friend)
Not online within the last half an hour
The last iteration of your for loop will always return yes as true. It needs to be less than, not thes than or equal to :)

And if this hasn't been posted already while I've been pondering over it, no it doesn't need to be $PHP_SELF, providing the page that script is on is called prime.php. It only really needs to be $PHP_SELF if he's changing the page name all the time.

edit: lol managed to post that 8 times in a row. Must be something wrong wit the double post checker.

________________
You know I'm a dancing machine
08.03.04 16:34
Post #3		Last edited: 08.03.04 16:39 (ZoGgEr! - 1 times) [Hide Sig (8)] [Profile] [Quote]
[]Dingbats
;
Send PM
An Avatar
Posts: 1970
Threads: 50
Mood: Optative
Money: £268.57 (D)
(+ Friend)
Not online within the last half an hour
I'll try it. And yep, the page is called prime.php.
Edit: No, it still doesn't work. :( Anyone else?
08.03.04 17:39
Post #4		Last edited: 08.03.04 17:46 (Dingbats - 1 times) [Softbrain Games] [Hide Sig (2)] [Profile] [Quote]
[S]Zogger!
Looking For Status
Send PM
Posts: 3954
Threads: 62
Money: £93.82 (D)
(+ Friend)
Not online within the last half an hour
oh it's divided by two... hmm...

________________
You know I'm a dancing machine
08.03.04 17:56
Post #5		 [Hide Sig (8)] [Profile] [Quote]
[]Dingbats
;
Send PM
An Avatar
Posts: 1970
Threads: 50
Mood: Optative
Money: £268.57 (D)
(+ Friend)
Not online within the last half an hour
Yep, it is. Since eg. 183/182 can't be working, get it?
08.03.04 17:58
Post #6		 [Softbrain Games] [Hide Sig (2)] [Profile] [Quote]
[S]CBWhiz
Looking For Status
Send PM
Posts: 1044
Threads: 130
Money: £1343.20 (D)
(+ Friend)
Not online within the last half an hour
\n
<?PHP\n

        for($i = $_GET["number"]; $i <= ($_GET["number"] / 2); $i++)<br />
\n?>
\n
should be
\n
<?PHP\n
for($i = $_GET["number"]; $i >= ($_GET["number"] / 2); $i--)
\n?>
\n

corse thats untested and only what i see at first glance
08.03.04 22:58
Post #7		 [Hide Sig (3)] [Profile] [Quote]
[B]C1
Looking For Status
Send PM
Posts: 0
Threads: 0
Money: £0.18 (D)
(+ Friend)
Not online within the last half an hour
wtf is a prime # counter? And what's the point of it? Help in math class lol?
09.03.04 04:29
Post #8		 [Hide Sig (2)] [Profile] [Quote]
[]The Pope
Decisive
Send PM
An Avatar
Posts: 5183
Threads: 123
Mood: Refreshed
Money: £201.52 (D)
(+ Friend)
Not online within the last half an hour
You know prime numbers right? Well this lets you type in a number and tells you if it is a prime number or not.

________________
Learn to look, look to learn.
09.03.04 07:49
Post #9		 [Hide Sig (14)] [Profile] [Quote]
[]Dingbats
;
Send PM
An Avatar
Posts: 1970
Threads: 50
Mood: Optative
Money: £268.57 (D)
(+ Friend)
Not online within the last half an hour
Thanks, Pope! Didn't think of that. Edit: WTF!!! It didn't work. Anyone else, please?:?
09.03.04 18:32
Post #10		Last edited: 09.03.04 18:34 (Dingbats - 1 times) [Softbrain Games] [Hide Sig (2)] [Profile] [Quote]
[B]C1
Looking For Status
Send PM
Posts: 0
Threads: 0
Money: £0.18 (D)
(+ Friend)
Not online within the last half an hour
Yes but what's the point pope. I kinda knew that part.
09.03.04 21:13
Post #11		 [Hide Sig (2)] [Profile] [Quote]
[]The Pope
Decisive
Send PM
An Avatar
Posts: 5183
Threads: 123
Mood: Refreshed
Money: £201.52 (D)
(+ Friend)
Not online within the last half an hour
Dingbats explained he felt bored and so decided to code something interesting. There was no actual reason.

I wish ppl would read threads fully...

________________
Learn to look, look to learn.
09.03.04 21:24
Post #12		 [Hide Sig (14)] [Profile] [Quote]
[B]C1
Looking For Status
Send PM
Posts: 0
Threads: 0
Money: £0.18 (D)
(+ Friend)
Not online within the last half an hour
Ah, i didnt see the text at the top of the code.
09.03.04 21:24
Post #13		 [Hide Sig (2)] [Profile] [Quote]
[]Dingbats
;
Send PM
An Avatar
Posts: 1970
Threads: 50
Mood: Optative
Money: £268.57 (D)
(+ Friend)
Not online within the last half an hour
HELPHELPHELPHELPHEL PNOW!1!1!
No, seriously. I've tried to change \n
for($i = $_GET["number"]; $i <= ($_GET["number"] / 2); $i++)
\n to \n
for($i = 0; $i <= ($_GET["number"] / 2); $i++)
\n, but that didn't work either. Please, can anyone help me?
10.03.04 18:41
Post #14		 [Softbrain Games] [Hide Sig (2)] [Profile] [Quote]
[S]ReadMe
Absent
Send PM
Posts: 2820
Threads: 85
Money: £43.42 (D)
(+ Friend)
Not online within the last half an hour
so if i'm following this script right, it tries to divide the number by all numbers less than it up to half it's value to see if you get whole number division, seems about right. I'd do it like this:

\n
<?PHP\n
$num = $_GET['number'];
for ($i=ceil($num/2);$i>1;$i--) {
if (($num % $i) == 0) {
$factor = true;
break;
}
}
$msg = ($factor) ? 'Sorry, not prime' : 'Wahey! Prime number' ;

\n?>
\n


FOOTNOTE:

if you need to use $_GET, then $PHP_SELF wont work either.

needs to be $_SERVER['PHP_SELF'] since register globals is off. This is a much better way to work btw - avoid any variable conflicts between GET vars and SESSION vars for example - always use superglobals.

________________
Cant be arsed to remake my sig.
10.03.04 22:17
Post #15		Last edited: 10.03.04 22:22 (ReadMe - 1 times) [Hide Sig (7)] [Profile] [Quote]
Page: [1] []

Post Reply

Jump To:

Your Comments:

Donate to BlameThePixel:
Donate to BTP Via PayPal


[22 Queries, Page Loaded in 0.228870 Seconds]

ShoutMeUp

Xmas Greetings from waka waka waka waka []Unvalidated EmailChristmasRiddle MERRY CHRISTMAS EVERYONE! []Spleet Except for Spleet. []TheAbdBoy Always bummin' a brother out. []Spleet Happy New Year everyone! But Spleet. []TheAbdBoy

Word Association

All

-10 Ago-

MiddleEastern []AlphaWolf camel [S]Bloopy toe []TheAbdBoy moose knuckle [S]Bloopy MeatLoaf []Spleet IdDoAnything4Lo ve []AlphaWolf rub n tug []TheAbdBoy tugboat []The Pope rope [S]Bloopy race []TheAbdBoy

-Latest-


Must be logged in to add new words

FictoLeague

You have to be logged in to vote...

Member Stats

Date: 03.05.24.
Members: 4731.
Latest: []Unvalidated Emailsdsakldsaldklasdsdsa
Active:
0 user(s)
1 guest(s)

On chat:
Lots of people

Files: 3330

Bloopy's Site
Get Firefox Get Opera Donate to BTP Via PayPal