A function for counting backward from an n value.

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HowDo

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Posted: 21st Jun 2005 03:29 Edited at: 21st Jun 2005 04:31

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Hi All

If I knew how spell the correct name for this code I would, anyway here it is.

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function Factorial(n)
   if n=<1
      exitfunction n
   else
      rem output to see what n is up to.
      text 0,400, "n="+str$(n)
      sync
      wait 100

         Factorial(n-1) * n
   endif
endfunction n
rem or
rem endfunction goal

{edit}
found the word and its recursive code.
[/edit]

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Sven B

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Posted: 21st Jun 2005 03:50

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You do know that you can count backwards this way too?

for i = 10 to 1 step -1

next i

I'm sorry but I don't really see the use of it...

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HowDo

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Posted: 21st Jun 2005 04:27

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Its for use in AI stuff allows you put your code in it, then do it again with a diffrent set of numbers, until you get the results you are after.

working on a connect 5 game.

Have a search on Alpha and Beta

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Frozen Flame

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Posted: 21st Jun 2005 12:43

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Could be useful for like a game where you have 20 seconds to defuse a bomb. and when bomb defused you can stop the countdown and show how many seconds there is remains.

Cool.

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Sven B

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Posted: 22nd Jun 2005 05:28

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Okay... and how do you use it?
The function is a loop on his own...

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HowDo

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Posted: 22nd Jun 2005 05:48 Edited at: 23rd Jun 2005 02:35

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just call from out side with a number like this

+ Code Snippet

Rem Project:
Rem Created: 6/21/2005 8:17:18 PM

Rem ***** Main Source File *****
rem Standard Setup Code
sync on : sync rate 0 :
backdrop on
color backdrop rgb(0,0,0) : hide mouse
set text font "arial" : set text size 12 : set text transparent

RANDOMIZE timer()
do

Factorial(rnd(30))

sync
loop

function Factorial(n)
   if n=<1
      exitfunction n
   else
      rem output to see what n is up to.
      text 0,400, "n="+str$(n)
      sync
      wait 100
if n=14 then text 0,100,"ho look I've come up Press a key to make me go away":sync:wait key:cls

         Factorial(n-1*n)
   endif
endfunction n

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Sven B

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Posted: 23rd Jun 2005 02:52

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Again, I don't see what it does...

It just gives a black screen and displays the same random number on 0,400 from time to time...

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Xolatron old

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Posted: 30th Jul 2005 16:41

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Sven B, it finds the factorial of n.
Factorial is:
1*2*3*4*5...*n
That 'random number' is n! = n factorial.

A simple example of what factorials are useful for:
You have 6 boxes of different colors. How many different ways can they be arranged in a line? 6 factorial.

-Xol

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The Nerd

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Posted: 30th Jul 2005 17:19 Edited at: 30th Jul 2005 17:25

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I would do it like this :

+ Code Snippet


For boom = 10 to 1 step -1
Print "Countdown : "+str$(boom)
Sleep 500
Next boom

Cls

Print "BOOOOOOOM!"

Wait key

End

I actually used that way in my first full game we're you should defuse a bomb.
But that's the way i use if i need to count a value backwards on it's own.
If it's a timer for a game i simple do like this :

+ Code Snippet


Time = 500

Do

Dec Time,1

Set Cursor 0,0
Print Time

If time < 1
Cls
Print "TIMES UP! GAME OVER!"
Wait key
End
Endif

sync
loop

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Xolatron old

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Posted: 30th Jul 2005 20:25

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HowDo's thread name is misleading. It is not 'counting backwards', but finding the factorial of a number - useful in math: probability especially.

HowDo is demonstrating how to compute the factorial of a number recursively - by calling the function in that function.

-Xol

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HowDo

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Posted: 30th Jul 2005 20:38

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Cheers Xolatron for explaining it, couldn't find the word recursively at the time of posting.

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Sven B

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Posted: 7th Aug 2005 23:45

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I see it now...
I thought he wanted to count backwards, like he said in the title...

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BatVink

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Posted: 9th Aug 2005 14:38

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It's a recursive function. Very powerful, and also very dangerous if you screw it up

It's a good way to set skill levels in games like chess. For a beginner, each piece may "look ahead" 2 moves, by recursively calling the algorithm twice. For Advanced, it may "look ahead" 10 moves, by resursively calling the algorithm 10 times.

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Code Snippets / A function for counting backward from an n value.