Random number genorator that doesn't repeat any numbers!!!

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The CodeSmith

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Posted: 20th Dec 2004 05:20

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How do I make a random number genorator that counts from 1 to 25 without repeating any number? The code I have included gives me 25 random numbers, but they do repeat themselves.
Thanks

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Zedane

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Posted: 20th Dec 2004 09:40

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you could do this the long way as in run the random number gen
rnd(25)+ 1 (1 to 25) and save the number in an array then do it again and if it matches any of the numbers in the array then have it not store that number but instead do it again untill it is a number that is not stored in the array

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ToXic

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Posted: 20th Dec 2004 11:41 Edited at: 20th Dec 2004 11:41

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Try this, example.

+ Code Snippet

Randomize Timer()
Dim Number(25)

For T=1 to 25
   Repeat
      OK=0
      N=Rnd(24)+1
      For C=1 to 25
         If Number(C)=N Then OK=1
      Next C
      If OK=0 Then Number(T)=N
   Until OK=0
Next T

For T=1 to 25
   Print Number(T)
Next T

Wait Key
End

ToXic.

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Mentor

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Posted: 22nd Dec 2004 06:25

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or do something like this

dim a(25)
for i=1 to 25
a(i)=i
print a(i)
next i
print
print
randomize timer()
for i=1 to 100
random1=int(rnd(24))+1
random2=int(rnd(24))+1
temp=a(random1)
a(random1)=a(random2)
a(random2)=temp
next i
for i=1 to 25
print a(i)
next i
wait key

all it does it start off with numbers 1 to 25 and then it shuffles them by picking two array locations at random and swapping the contents over, so your orderly list of numbers get shuffled, faster for large quantitys of numbers than checking for matches each pass, hope thats some help.

Mentor.

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BadMonkey91

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Posted: 22nd Dec 2004 20:31 Edited at: 22nd Dec 2004 20:38

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+ Code Snippet

randomize timer()
dim oldz(25)

for x=1 to 25
again:
z=rnd(25)

test:
oldz(x)=z
for f=1 to 25
if z = oldz(f) then z=z+1 : goto test
next f

if z > 25 then goto again
if z=0 then goto again
next x

maybe that

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BigDan256

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Posted: 22nd Dec 2004 21:30 Edited at: 22nd Dec 2004 22:09

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This one should always run the same amount of time, think it's O(n^2/2)
The seq() array will be the resulting order of numbers

+ Code Snippet

dim seq(25)
dim used(25)

for i=1 to 25
   j=rnd(25-i)+1
   for k=1 to j
      if used(k) then inc j
   next k
   seq(i)=j
   used(j)=1
next i

Or if you'd like more control over the length of time it takes to generate, and use less memory, this one should be O(n), where n is chosen by yourself

+ Code Snippet

dim seq(25)
n=625

for i=1 to 25
   seq(i)=i
next i

for i=1 to n
   a=rnd(24)+1
   b=rnd(24)+1
   temp=seq(a)
   seq(a)=seq(b)
   seq(b)=temp
next i

Edit: I just noticed Mentor had already suggested this last one

Here's a nice game of pickup 52

+ Code Snippet

dim floor(52)
dim hand(52)

`Drop all the cards on the floor
for i=1 to 52
   floor(i)=i
next i

`Count where all the cards are
floorcount=52
handcount=0

`While there are still cards on the floor
while floorcount>0

   `Choose a card on the floor
   floor_id=rnd(floorcount-1)+1
   card=floor(floor_id)

   `Put the card in our hand
   inc handcount
   hand(handcount)=card

   `Remove the card from the floor
   floor(floor_id)=floor(floorcount)
   dec floorcount

endwhile

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DarkBASIC Discussion / Random number genorator that doesn't repeat any numbers!!!