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 P: n/a Hi, I want to do some calculation like ( t1 and t2 are known) for i = t1 to t2 for j = t1 to t2 ..... ..... for p = t1 to t2 for q = t1 to t2 some actions next next ....... next next but i know only the number for next in run time with the variable iTimes Is there a solution for this problem? Thanks for any response Jul 12 '06 #1
13 Replies

 P: n/a "andreas" V B Jul 12 '06 #2

 P: n/a And those actions are ? How do they depend on loop variables ? IMO this is the main problem... For exaple you could just use a single loop (doing 4 times 10 loops would be the same than doing a loop 40 times) -- Patrice "andreas"

 P: n/a yes, Herfried "Herfried K. Wagner [MVP]" V B Jul 12 '06 #4

 P: n/a it is not possible to change the 4 times 10 loops in 40 loops because i do something with i, j,k ... "Patrice"

 P: n/a If you do something with an unknown number of variables you could use an array instead of using i,j,k etc... You'll just have a single loop in which you'll increment the appropriate element of the array for use in your actions... If you prefer and have a maximum possible number of loops you could also use start=stop for some of the loop so that they are done only once when appropriate etc... -- Patrice "andreas" And those actions are ? How do they depend on loop variables ? IMO thisisthe main problem...For exaple you could just use a single loop (doing 4 times 10 loops would be >the same than doing a loop 40 times)--Patrice"andreas"

 P: n/a andreas wrote: I want to do some calculation like ( t1 and t2 are known) for i = t1 to t2 for j = t1 to t2 ..... ..... for p = t1 to t2 for q = t1 to t2 some actions next next ....... next next but i know only the number for next in run time with the variable iTimes One possible approach would be to use a single function controlled by iTimes: if iTimes was 0, it would perform the specified action, otherwise it would call itself recursevelly, decrementing iTimes. The matters complicate a little because you want the respective indexes of each loop, but these can be kept in a stack and accessed by the 'action' sub. An air-code example of this approach could be: Class NestedLoop Protected ReadOnly Stack As New Stack(Of Integer) Protected ReadOnly Min As Integer Protected ReadOnly Max As Integer Protected Levels As Integer Sub New(Levels As Integer, Min As Integer, Max As Integer) Me.Min = Min Me.Max = Max Me.Levels = Levels End Sub Protected Sub Execute DoLoop(Levels) End Sub Protected Overridable Sub Action() End Sub Private Sub DoLoop(Level As Integer) If Level = 0 Then Action Else For I As Integer = Min To Max Stack.Push(I) DoLoop(Level - 1) I = Stack.Pop Next End If End Sub End Class Then, it would be just a matter of inheriting from the class and overriding the method Action, adding to the derived class whatever new properties you'd like. Class SimpleLoop Inherits NestedLoop Public ReadOnly Result As Integer Public Sub New(Levels As Integer, Min As Integer, Max As Integer) MyBase.New(Levels, Min, Max) Execute End Sub Protected Overrides Sub Action Result += 1 End Sub End Class Finally, to invoke the action, you could use something like this: Dim ActionResult As New SimpleLoop(iTimes, T1, T2) Presto! =) HTH. Regards, Branco. Jul 12 '06 #7

 P: n/a Branco, Not easy for me to understand all but I think this is the solution for my problem. Thank you and everyone. "Branco Medeiros" One possible approach would be to use a single function controlled by iTimes: if iTimes was 0, it would perform the specified action, otherwise it would call itself recursevelly, decrementing iTimes. The matters complicate a little because you want the respective indexes of each loop, but these can be kept in a stack and accessed by the 'action' sub. An air-code example of this approach could be: Class NestedLoop Protected ReadOnly Stack As New Stack(Of Integer) Protected ReadOnly Min As Integer Protected ReadOnly Max As Integer Protected Levels As Integer Sub New(Levels As Integer, Min As Integer, Max As Integer) Me.Min = Min Me.Max = Max Me.Levels = Levels End Sub Protected Sub Execute DoLoop(Levels) End Sub Protected Overridable Sub Action() End Sub Private Sub DoLoop(Level As Integer) If Level = 0 Then Action Else For I As Integer = Min To Max Stack.Push(I) DoLoop(Level - 1) I = Stack.Pop Next End If End Sub End Class Then, it would be just a matter of inheriting from the class and overriding the method Action, adding to the derived class whatever new properties you'd like. Class SimpleLoop Inherits NestedLoop Public ReadOnly Result As Integer Public Sub New(Levels As Integer, Min As Integer, Max As Integer) MyBase.New(Levels, Min, Max) Execute End Sub Protected Overrides Sub Action Result += 1 End Sub End Class Finally, to invoke the action, you could use something like this: Dim ActionResult As New SimpleLoop(iTimes, T1, T2) Presto! =) HTH. Regards, Branco. Jul 12 '06 #8

 P: n/a andreas wrote: Branco, Not easy for me to understand all but I think this is the solution for my problem. It's actually quite simple. When you create an instance of a class derived from NestedLoop, it initializes the loop parameters with a call to MyBase.New(). The class must then call the protected method Execute, which will actually start the loop by calling the private method DoLoop in the base class. The DoLopp method just checks the current nest level: if it's 0 then it calls the virtual method Action, otherwise it starts a new loop in the specified range and calls itself recursivelly, decrementing Level as it goes. This way there will be N recursive DoLoop calls, corresponding to the number of levels you specified. For all effects, they act as the nested loops from your original post. I guess you can see that the Action method is the one that you must override in your derived classes. It corresponds to the methods executed inside the most inner loop in the example you gave originally. Now notice that the number of times Action will be executed is exponencial to the number of levels, corresponding to ((Max - Min) + 1) ^ Levels. For instance, with Min=1, Max=10 and Levels = 10, the Action method will be called 10^10 times, that is, 10000000000 times... =)) Regards, Branco. Jul 12 '06 #9

 P: n/a Thanks Branco for your explanation "Branco Medeiros"

 P: n/a To make my problem clear: I want to have in a array (wich I can redim in runtime) of strings the following Choice to make in runtime : Or "11","01","10",00 Or "111","110","101","100","011","010","001","000 " Or "1111","1110",1101","1100","1011",............ ... .............. Or "111111111111","111111111110","111111111101",. .... ....... and so on Is the method of Branco, wich I thank, the only solution? "andreas"

 P: n/a That is you want to print out all binary numbers for a given length ? If yes, a simple loop going from 0 to 2^length-1 will enumerate all possible values. Then print out each value using the binary format... -- Patrice "andreas" Hi,I want to do some calculation like( t1 and t2 are known)for i = t1 to t2 for j = t1 to t2 ..... ..... for p = t1 to t2 for q = t1 to t2 some actions next next ....... nextnextbut i know only the number for next in run time with the variable iTimesIs there a solution for this problem?Thanks for any response Jul 13 '06 #12

 P: n/a andreas wrote: I want to have in a array (wich I can redim in runtime) of strings the following Choice to make in runtime : Or "11","01","10",00 Or "111","110","101","100","011","010","001","000 " Or "1111","1110",1101","1100","1011",............ ... ............. Or "111111111111","111111111110","111111111101",. .... ...... and so on In this case, maybe the following function works for you: Function BinaryRange(ByVal Times As Integer) As String() Dim Max As Integer = (2 ^ Times) - 1 Dim Result(Max) As String For I As Integer = 0 To Max Result(Max - I) = Convert.ToString(I, 2).PadLeft(Times, "0"c) Next Return Result End Function It retursns an array of strings built with the binary of the numbers from (2^Times) - 1 down to 0, i.e., for Times = 4, it would be "1111", "1110", "1101", "1100", "1011", "1010", "1001", "1000", "0111", "0110", "0101", "0100", "0011", "0010", "0001" and "0000". HTH. Regards, Branco. Jul 13 '06 #13

 P: n/a Thanks to Branco and all the others Branco, what you wrote is very simple and clever. I feel a litle stupid, but thanks, thanks, thanks.8 "Branco Medeiros" andreas wrote: I want to have in a array (wich I can redim in runtime) of strings the following Choice to make in runtime : Or "11","01","10",00 Or "111","110","101","100","011","010","001","000 " Or "1111","1110",1101","1100","1011",............ ... ............. Or "111111111111","111111111110","111111111101",. .... ...... and so on In this case, maybe the following function works for you: Function BinaryRange(ByVal Times As Integer) As String() Dim Max As Integer = (2 ^ Times) - 1 Dim Result(Max) As String For I As Integer = 0 To Max Result(Max - I) = Convert.ToString(I, 2).PadLeft(Times, "0"c) Next Return Result End Function It retursns an array of strings built with the binary of the numbers from (2^Times) - 1 down to 0, i.e., for Times = 4, it would be "1111", "1110", "1101", "1100", "1011", "1010", "1001", "1000", "0111", "0110", "0101", "0100", "0011", "0010", "0001" and "0000". HTH. Regards, Branco. Jul 13 '06 #14

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