shuffle a deck of 51 cards problem

[addie1125]

i am doing a procedure to shuffle a deck of 51 cards
this is a procedure in a class
this is not working
can you help me ? thank you very much ~>_<~

var Card : array 0 .. 51 of int % global variable for the class

procedure shuffleDeck
for i : 0 .. 51
Card(i) := i
end for

for decreasing j : 51 .. 0
k := Rand.Int (0, j)
Card(k) := Card(j)
end for
end shuffleDeck

-------------------------------------

the numbers this thing puts do not repeat...

for i : 0 .. 51
Card(i) := i
end for

for decreasing j : 51 .. 0
k := Rand.Int (0, j)
Card(k) := Card(j)
end for

[chrisbrown]

1) Use code tags, i.e [_Code_] Some code [_/Code_] but without the underscores.
2) Look at your shuffle procedure- assuming you've defined k, you're setting some random card in the deck to be the jth (last, sort of) card in the deck, but you don't remove that jth card so thats why you have duplicates.
Visually, if k = x:

code:

[ ... x y z ... j ]

becomes

code:

[ ... x j z ... j ]

What you need to do is swap the cards, not just reassign one of them (each time around the loop).

3) The range 0 .. 51 contains 52 elements so you actually have a standard 52 card deck there.
4) The first for loop in shuffle is not needed. You don't need to reset your deck each time you shuffle it.