how to dont Repetition Random number

[dev4you]

hi
i have question how can i Random numbers with out Repetition
i use this code and its show this error in Emluter

java.lang.arrayindexoutofboundsexception

Dim x() as Boolean

i= rnd(1,20)
if x(i) = false then
'conition1
Else
x(i) = false
end if

now that I tried other codes such as

Dim x() as string

i= rnd(1,20)
if x(i) = "false" then
'conition1
Else
x(i) = "false"
end if

and still the same problem

 

[LineCutter]

If you're trying to do what I think you're trying to do they you're not generating random numbers so much as shuffling cards (20 of them).

There is basic4PPC code here that will show you how to do that.

Oh also, x() doesn't look like it's been initialised so you can test for "false" in the original code.

 

[dev4you]

thanks for you

but when i open this file there is no any code

please how can i open it

 

[Erel]

See this link: http://www.b4x.com/forum/basic4android-share-your-creations/7774-card-game-shell-programmers.html

 

[dev4you]

Erel thank you
but i'm beginner i dont understand this example
can you put to me simple example code to Generates number from 1-10
and dosent Repeat any number
thanks Again

 

[Erel]

Here:

Sub Activity_Create (FirstTime As Boolean)
   Dim numbers(10) As Int
   'put numbers 1 - 10 in the array
   For i = 0 To 9
      numbers(i) = i + 1
   Next
   ShuffleArray(numbers)
   For i = 0 To 9
      Log(numbers(i)) 'print the numbers to the log
   Next
End Sub

Sub ShuffleArray(arr() As Int)
   For i = arr.Length - 1 To 0 Step -1
      Dim j, k As Int
      j = Rnd(0, i + 1)
      k = arr(j)
      arr(j) = arr(i)
      arr(i) = k
   Next
End Sub

Based on this algorithm: Fisher–Yates shuffle - Wikipedia, the free encyclopedia

 

[dev4you]

Erel
thanks for you :sign0148:

but :sign0013: can you write to me the full code that
i want when i click on button1 that generate random number "whit out repeat" in label1

thank you very much Erel :sign0085:

 

[timo]

x Dev4you:

Sub Button1_Click
'(put the code directly in the button)

Dim numbers(10) As Int
'put numbers 1 - 10 in the array
For i = 0 To 9
numbers(i) = i + 1
Next
ShuffleArray(numbers)
For i = 0 To 9
Log(numbers(i)) 'print the numbers to the log
Next

'goes here:
Label1.Text=numbers(0)
Label2.Text=numbers(1)
Label3.Text=numbers(2)
'....
'etc

End Sub

Sub ShuffleArray(arr() As Int)
For i = arr.Length - 1 To 0 Step -1
Dim j, k As Int
j = Rnd(0, i + 1)
k = arr(j)
arr(j) = arr(i)
arr(i) = k
Next
End Sub

 

[dev4you]

than you timo sooooo much