Rand function not very random

Anon

I have a script that sets a variable and uses it to change the order of a correct answer.

Out of 15 calls to this script, Here's the spread:

Result number w/this result
0 10
1 4
2 1
3 0

This has been the CONSISTANT result. The majority get grouped in ZERO, and RARELY hit 3 (but they DO hit 3)

What am I doing wrong?

Here's what I loop to check the value:

$pos = rand(0,3);
$j = 0;
for ($i=0; $i<4; $i++)
{
if ($pos == $i) {
// this is the correct one!
echo "<input type=\"radio\" value=\"1\" name=\"r1\">";
echo $myq->anscorrect, "<br>";
} else {
echo "<input type=\"radio\" name=\"r1\" value=\"0\">";
$j++;
if ($j == 1) echo $myq->ans1, "<br>";
if ($j == 2) echo $myq->ans2, "<br>";
if ($j == 3) echo $myq->ans3, "<br>";
} // elseif pos = $i;
} // for i

Anon

(1) are you using srand() before this to set the starting value?

(2) you should be using mt_rand() anyway: it's both mathematically better, and faster performing. But (1) still applies: you have to call mt_srand() to initialize it.

Anon

Absolutely correct. Never having used the function, I found it in the manual and saw no reference to srand(). I'll also check out mt_rand().

Thanks!

Anon

That's funny...in my manual, at www.php.net, it says:

If called without the optional min, max arguments rand() returns a pseudo-random value between 0 and RAND_MAX. If you want a random number between 5 and 15 (inclusive), for example, use rand (5, 15).

Remember to seed the random number generator before use with srand().

Notice the second line....

---John Holmes...