14 replies to this topic

[shibbythestoner]

I've tried changing a number of things and asked a friend but I'm stumped: this function I wrote should return a string, but instead it seems to ignore the for loop.
Perhaps someone here could tell me what I've done wrong?

    mt_srand(time());
    
    $letters=array("a","b","c","d","e","f","g","h","i","j","k","l","m","n","o","p","q","r","s","t","u","v","w","x","y","z",
                "A","B","C","D","E","F","G","H","I","J","K","L","M","N","O","P","Q","R","S","T","U","V","W","X","Y","Z",
                "0","1","2","3","4","5","6","7","8","9",
                "10","13","1337","2008","fail","wat","n00b","fake","luvz","php",
                "_");
    $letno=(count($letters)-1);
    
    function cstr($length, $randlen){
        $string="";
        if ($randlen){
            $length=mt_rand(1, $length);
        }
        for ($i=0; $i < ($length+1); $i++){
            $string=$string.$letters[(mt_rand(0,$letno))];
        }
        return $string;
    }

FYI, $randlen is a boolean, I tend to send true/false through; but have also tried 1/0 to no avail.
An example of how I call the function:

$email_address=cstr(20,true)."@".cstr(20,true).".".cstr(3,false);

This makes $email_address:

@.

Any ideas would be greatly appreciated.

[Lop]

Put an 'echo' function in the for loop. If you see print xx times you know the for loop is being executed.

The reason I say this is because your variables, $letters and $letno, are out of scope. You need to declare them in the function with

global $letters, $letno;

You probably want to seed your rand in the function as well.

[shibbythestoner]

Thanks, Lop, I'll give it a go.

[shibbythestoner]

Worked like a charm, Lop! Well...certainly on my test version on localhost; so I'm assuming the same will apply to my larger script. Thanks very much.

[shibbythestoner]

I'm afraid I've come accross a problem - most of the strings generated in one go seem to be identical or just a couple characters off identical...perhaps this is because the script runs very fast and the randomisation is seeded using time?
Any solution for this?

[shibbythestoner]

Never mind, use of sleep() is sufficient for what I need it for.
Thanks for your help, Lop.

[Lop]

You could also try PHP: microtime - Manual instead of time()

[shibbythestoner]

Lop said:

You could also try PHP: microtime - Manual instead of time()

Looks useful, thanks.

[shibbythestoner]

4.4.7 on my site's server.
Interesting, so I don't need to seed randomisation...
Thanks for the info.

[Lop]

I forgot about that. It is weird that you seeded it (even though you didn't need to) and the number still came out close. If you don't seed and don't pause is there enough randomness?

[shibbythestoner]

Well the results didn't matter a huge amount and I only needed to run the script once, so I haven't modified that script (yet). So I couldn't say.