Question

I want to run something like this:

For a = 0 To 4
   For b = a To 4
      For c = b To 4
        Console.WriteLine(a & b & c)
      Next
   Next
Next

But I need to create n loops one each other. So I created this method:

'iFrom = 0; iTo = 4; Depth = 3(loop count);
Private Sub Iterate(ByVal iFrom As Integer, ByVal iTo As Integer, ByVal Depth As Integer)
    For i = iFrom To iTo
       If Depth - 1 > 0 Then Iterate(iFrom, iTo, Depth - 1)

       'Do stuff here
    Next
End Sub

What would be the best way to retrieve the “i” values from higher levels? Should I store them in an array? Or is there a completely different way to approach this problem?

Answer 1

After playing around with this method I finally found the solution. Here it is:

Private Sub Iterate(ByVal iFrom As Integer, ByVal iTo As Integer, ByVal Depth As Integer, ByVal iValues As Integer())
    For i = iFrom To iTo
        iValues(Depth - 1) = i
        If Depth - 1 > 0 Then
            Iterate(i, iTo, Depth - 1, iValues)
        Else                
            'Do stuff, in this case print the current iValues
            Console.WriteLine(String.Join("", iValues.Select(Function(x) x.ToString).ToArray))                
        End If
    Next
    Console.WriteLine()
End Sub

'Usage:
Dim iValueArray(Depth) As Integer
Iterate(0, 1, 2, iValueArray)