13.9. Shuffling and dealing¶
In Section 1.6 I wrote pseudocode for a shuffling
algorithm. Assuming that we have a function called
takes a deck as an argument and shuffles it, we can create and shuffle a
Deck deck; // create a standard 52-card deck deck.shuffleDeck (); // shuffle it
Then, to deal out several hands, we can use
Deck hand1 = deck.subdeck (0, 4); Deck hand2 = deck.subdeck (5, 9); Deck pack = deck.subdeck (10, 51);
This code puts the first 5 cards in one hand, the next 5 cards in the other, and the rest into the pack.
When you thought about dealing, did you think we should give out one card at a time to each player in the round-robin style that is common in real card games? I thought about it, but then realized that it is unnecessary for a computer program. The round-robin convention is intended to mitigate imperfect shuffling and make it more difficult for the dealer to cheat. Neither of these is an issue for a computer.
This example is a useful reminder of one of the dangers of engineering metaphors: sometimes we impose restrictions on computers that are unnecessary, or expect capabilities that are lacking, because we unthinkingly extend a metaphor past its breaking point. Beware of misleading analogies.
The active code below deals a deck of cards among three players for a game of Go Fish. Feel free to experiment with the code and deal decks for other games like War, Poker, and Egyptian Ratscrew.