http://www.shoesobjects.com/blog/tags/random/ My thoughts on software, technology, and life in general en Mike Shoemaker Sun, 31 Jan 2010 17:47:37 GMT Pebble (http://pebble.sourceforge.net) http://backend.userland.com/rss http://www.shoesobjects.com/blog/2005/12/01/how_would_you_write_a_shuffle_algorithm.html <p> As I'm beginning to write my card game application, I've approached the unit test where I need to shuffle the deck. I've implemented it based on Knuth's Shuffle algorithm. My question is, what are some clever ways that other programmers have implemented it? </p> <p> My current implementation works like this. </p> <ul> <li>Put all 52 cards in an array</li> <li>For Loop starting at element 51, working backwards</li> <li>Generate random number between 0 and loop element index</li> <li>Swap current element card with the element at the random index generated in previous step</li> <li>Finish when loop index reaches the zero element. </li> </ul> <p>&nbsp;</p> <p> Delima with current implementation </p> <ul> <li>Is there a bias with generating a random number between 0 and the loop index? I'm doing so with java.util.Random</li> <li>Would multiple shuffle iterations over the deck solve this?</li> <li>Is it worth refactoring the shuffle algorithm to use the strategy pattern so I can have multiple implementations of shuffle? After all, this is a simple command line game, not Harrah's next killer online gambling app.</li> </ul> <p>&nbsp;</p> java http://www.shoesobjects.com/blog/2005/12/01/how_would_you_write_a_shuffle_algorithm.html#comments http://www.shoesobjects.com/blog/2005/12/01/how_would_you_write_a_shuffle_algorithm.html Fri, 02 Dec 2005 05:59:32 GMT