Question

I am trying to get a program to reiterate until both the $heads variable and $tails variable is greater than 0. I can’t figure out what I am doing wrong. The while loop always gets broken after just one iteration.

<?php
echo "<table border=\"1\">";
echo "<tr><td>Person</td><td>Heads</td><td>Tails</td><td>Total</td></tr>";



for ($person=1; $person < 11; $person++){
echo "<tr><td>Person $person </td>";
$both = 0;
$heads = 0;
$tails = 0;
$total = 0;
while ($both < 1){
    do {
        $total++;
        $random = rand(1,2);
        if ($random == 1){
            $heads++;
        } else{
            $tails++;
        }  
    } while (($tails < 0)  && ($heads < 0));
    $both = 1;

}
echo "<td>$heads</td><td>$tails</td><td>$total</td>";
echo "</tr>";

}

echo "</table>";

?>

Answer 1

In this line

} while (($tails < 0)  && ($heads < 0));

it appears that neither $tails nor $heads will ever be strictly less than 0, so that will always be false. Try <= 0 for both.

Also, logically, you want to loop again if either of those conditions is true, right? So use || instead of &&.

Result:

} while (($tails <= 0) || ($heads <= 0));

---

Also, I’m a little curious about the while ($both < 1) loop. It appears that you assign $both = 0 before the loop, and you assign $both = 1 at the end of its iteration. That would guarantee the loop is only executed once, in which case — what’s the point of having that loop? Perhaps that’s just unfinished code at this point?