Question

I recently started a little project in PHP, I’m sort of new to this and this may be a beginner question but I can’t find any help so I’m asking here.

I am working on a card game and I want to give up to six players random cards. I store how many cards everyone gets in $cardstoget and how many players there are in $player. I have an array $usedcards with values like [0] => 0, [1] => 0 and so on. I determine if the card is already used by putting it to 1 instead of 0 like this: [1] => 1. There are 80 cards and I plan on having [0] filled with the number of unused cards left.

I use this code:

for ($i = 1;$i <= $player;$i++) {
 for ($i2 = $cardstoget;$i2 > 0;$i2--) {
  do {
   $temp = mt_rand(1,80);
  } while ($usedcards[$temp] = 1);
  ${"cards".$i} = ${"cards".$i} . $temp;
  $usedcards[$temp] = 1;
 }
}

When I execute the code I get this error message:

Fatal error: Maximum execution time of 30 seconds exceeded in /var/www/create.php on line 47

So now to my question: How can I change the do-while loop to make it to something similar but faster? I know this loop is the problem, I tried it without and it worked fine,but I can’t know it this card is already on someone’s hand.

I hope somebody out there can help me and any help is highly appreciated.

Answer 1

Your immediate problem is the $usedcards[$temp] = 1 condition. You’re assigning 1 here, which results in the condition always being true, and the loop looping endlessly.

More generally, you’ll want a deterministic algorithm, not one whose completion depends on randomness. Something like:

$cards = range(1, 80);
shuffle($cards);

for ($i = 0; $i < $cardsPerPlayer; $i++) {
    foreach ($players as &$player) {
        $player['cards'][] = array_shift($cards);
    }
    unset($player);
}

This mimics a real shuffling-and-distribution of cards as you’d do in a real game.