# generating a series for all 2 power n combinations in vb.net

I have n items and each item can be assigned a 1 or a 2. So I would like to get the matrix result that would generate all possible combinations.
For eg. if n= 3 , then the possible outcomes are : I  need an algorithm that can generate this series for n . Please help thanks. ideally i would like to store the result in a datatable

1 1 1
1 1 2
1 2 1
2 1 1
2 1 2
1 2 2
2 2 1
2 2 2
Asked:
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Commented:
``````        Dim HighestValue As Integer = 2 ' max value
Dim NrOfValues As Integer = 3 ' nr of values in one result
Dim Values(NrOfValues) As Integer
Dim i As Integer
For i = 0 To NrOfValues - 1
Values(i) = 1
Next
Values(NrOfValues - 1) = 0 ' to generate first as ALL 1
For i = 1 To HighestValue ^ NrOfValues
Values(NrOfValues - 1) += 1
For j As Integer = NrOfValues - 1 To 0 Step -1
If Values(j) > HighestValue Then
Values(j) = 1
Values(j - 1) += 1
End If
Next
Dim Result As String = ""
For j As Integer = 0 To NrOfValues - 1
Result = Result & CStr(Values(j))
Next
Debug.WriteLine(Result)
Next
``````
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Commented:
Logic is

2^0 2^0 2^0
2^0 2^0 2^1
2^0 2^1 2^0
2^0 2^1 2^1
2^1 2^0 2^0
2^1 2^0 2^1
2^1 2^1 2^0
2^1 2^1 2^1

The power to the num 2 is binary seris

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Author Commented:
Thank you both for the suggestoins. Both the suggestions are great and made me understand the concept behind.

Ambusy, the code you provided just works great and does exactly what I wanted.

Just one question, if I change     HighestValue , and NrOfValues  then this logic should just work for any number of items and any number of possible values for each item right?

thanks again.
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Commented:
Exactly, that's why I wrote them as variables. I tested them with values in a textbox to be certain it workes.
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Commented:
If my solution is correct, please accept it.
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Author Commented:
the solution works great. does exactly what I want
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