View source for TI-BASIC:Deck Of Cards

{{Template:TI-BASIC:Routine
|picture=@@
|summary=Simulates a standard 52-card deck of cards.
|input=None
|output=''∟DECK'' - the cards, in the format:

Value.Suit

Value is 1..13
Suit is 0, .25, .5, .75
|variable=L₁, ∟DECK
|compatibility=TI-83/84/+/SE
|author=@@
|authors=@@
|url=@@
|download=[file deckofcards.zip]
}}

'''Creating the deck'''

 seq(X/4,X,4,55→DECK

'''Shuffling the deck'''

 rand(52→L₁
 SortA(L₁,∟DECK

'''Accessing individual cards'''

 ∟DECK(I
 Disp "VALUE:",sub("A23456789TJQK",int(Ans),1 
 Disp "SUIT:",sub("SHCD",4fPart(Ans)+1, 1


The cards in the deck are stored in the form Value.Suit, where the value of the card (Ace through King) is encoded as a number 1 through 13; and the suit of the card is the fractional part, encoded as one of 0, 0.25, 0.5, or 0.75. In the above code (accessing individual cards), the convention is that 0=Spades, 0.25=Hearts, 0.5=Clubs, 0.75=Diamonds; however, you can pick any order as long as you're consistent.

Since any value from 1.00 to 13.75, that's 1/4 of an integer, is a valid card, we can generate the entire deck as 1/4 of the values {4,5, ..., 54, 55}.

When shuffling the deck, we generate a random list in L₁, then use [[TI-BASIC:Sorta|SortA(]] to sort ∟DECK by the values in L₁. Since the values in L₁ are random, this has the effect of sorting ∟DECK in a random order.

The main overhead of this shuffling method, however, is that generating a random list might take a long time (around a second or two). To avoid this, you can generate individual elements of L₁ randomly in a [[TI-BASIC:Getkey|GetKey]] loop, while waiting for a key, then use L₁ to shuffle later. Since shuffling isn't done often, by the time you need to shuffle, L₁ will most likely be fully randomized already.

Finally, accessing the cards is done using [[TI-BASIC:Fpart|FPart(]] and [[TI-BASIC:Int|Int(]]. If a variable X is encoded in the same way that we encode cards, int(X) will return its value (1-13) and 4fPart(X)+1 will return its suit as a number 1-4.[[Category:TI-BASIC]]
[[Category:TIBD]]