timer problem

universelittle

I have searched for a long time, but still can't find any helpful codes. I want to produce a random number every 10 seconds, can anyone tell me how to do that? Thanks!

mrmufin

In what context do you want this to happen? The individual pieces required to do this are quite simple:

// first seed the random number generator. There's better ways to do this, but this'll work for now:
srand(time());

// print out a random number between 1 and 2000
echo rand(1, 2000);

// sleep fer 10 seconds:
sleep(10);

But this is quite annoying to run, thanks to the ten-second sleep. If I'm just clicking into a page, it better of some damn good stuff there for me to stick around for more than 10 seconds, just to see the next random number spit out...

Which is why I ask about the context... do give more details, and perhaps myself, or someone else here, can provide a much better solution...

universelittle

Thank you very much!🙂

What's relationship between srand() and rand()?

I am using php4.2.2 and MySQL3.2. I have some stock price in
MySQL database, in order to simulate the real-time stocks, I want
the stock price change randomly within a range whether up or down from time to time.

I have some problems:

Which way is better to display the random price on a webpage?first make the data stored in database randomly changed, then extract the changed data from database to display on the
webpage / or first extract the static data from database and
then make it randomly changed?
How to make the webpage automatically refreshed once the data has updated?

[/B]

mrmufin

I think I kinda sorta somewhat slightly understand what you wanna do...

Pull the 'stock price' outta the database. Leave that consistent, static, non-random. Let's suppose the stock price is 10. To 'simulate' changes in the stock price, you know it's '10' in the database, so set your range (say +/- 2), based on the stock price...

// Seed the random number generator. Whenever you do something that's random, the rand() function needs a starting point, a 'kicker', a little nudge, if you will. That's what srand() is for.

srand(time());

// We've selected the 'static' stock price from the database, and we know it's 10. We know our range will be +/- 2. Use yer own values, if you don't like mine. So we're going to generate a random number between (10 -2) and (10 + 2). 

// Since it's kinda cheesy to only display *whole* numbers for stock prices, and that's what the rand() function delivers, we'll apply a little math in order to get 'dollar' values:

// stock price is 10, we'll typecast it as a float:
$sp = (float)10;

// our range is +/- 2:
$r = (float)2;

// now, we echo a random value:
echo rand((($sp - $r) * 100), (($sp + $r) * 100)) / 100;

// Reload the page, and the simulated 'stock price' is changed. Automatically. No need to screw around with sleep() or anything else.

Any help there?

universelittle

Thank you for your great help! 🙂
It works well! But how to make it refresh itself automatically once the price changed?

According to your code, I made it like this:

<?
function ranNum($sp){

   srand(time());
   $sp = (float)$sp;

   if ($sp<1) {
      $r = (float)0.5;
      echo rand((($sp - $r) * 1000), (($sp + $r) * 1000)) / 1000;
   }   

   else {
      $r = (float)2;  

      echo rand((($sp - $r) * 100), (($sp + $r) * 100)) / 100;
   }               

}

ranNum(10);
?>

mrmufin

Are you sure you want it do refresh when the price has changed??

Suppose I'm reading your webpage, and it takes 12 seconds to download on my 56k modem. I'm in the middle of a bitchin' article, and the page reloads on me, without me clicking on anything... Now I'm not a happy camper because my 'viewing experience' was interrupted by your stock ticker, which I may or may not be interested in...

As a web user, I'm quite satisfied with a 'click here to get the current stock price' link or button. I suppose there are methods which could be used (like META tags with refresh:URL settings), etc... but I haven't done that shtuff in a while. To drive it from the server-side, (er, now the price has changed, so send a new page to the client, whether he likes it or not) requiers some sort of trigger event. (like an affirmative request from the client...)

You could put the stock ticker portion in it's own frame in a framesetted page, to help minimize unwarranted page reloads, but again, that's stuff that I haven't worked with in a while...

Perhaps there's other folks out here with brains bigger than mine who could help you out with that...

universelittle

Thank you, mrmufin!

<META HTTP-EQUIV="Refresh" CONTENT="3; URL=http://localhost/testRand.php"> can auto refresh my page successfully.

But now I wonder how to only auto refresh part of the page like a table without affecting other parts? But I don't want to use frame.😕

mrmufin

Well, you're kinda stuck with one of:

1) refreshing a single frame

2) refreshing the whole page

3) using some other technique (like Java), which some of us keep disabled, for good reason.

Good luck