how do i write this for vb.net

Question

hi. i am translating c code to vb.net code. i am new with this language. basically i had translate it without any error but it doesnt work as what i want. can anyone help me with this.i got this code from a book i read. #include #define VERTEXNUM 4 #define HUGE 32000 const char *vertices [] ={ selandar chinchin jasin merlimau }; const int edges [VERTEXNUM][VERTEXNUM] ={ {0221632} {2201526} {1615021} {3226210} }; int visited [VERTEXNUM] ={0}; int curMinCost = HUGE; int curMinHamNum = 0; int currentRoute [VERTEXNUM]; void findRoute (int start int current int costSoFar int numVisited); void foundHamiltonian (int start int cost); int main (void) { int start = 0; int j; for (j=0; j if (j != start) findRoute (start j edges [start][j]0); printf(lowest cost hamiltonian cycle: %d w/ cost %d
 curMinHamNum curMinCost); getchar(); return (0); } void findRoute (int start int current int costSoFar int numVisited) { int j; currentRoute[numVisited]=current; if (current == start) { if (numVisited == VERTEXNUM -1) foundHamiltonian (start costSoFar+edges[current][start]); } else { visited[current] = 1; for (j=0; j if (!visited[j]) findRoute(startjcostSoFar+edges[current] [j] numVisited+1); } visited[current] = 0; } } void foundHamiltonian (int start int cost) { int j; static int hamNum=0; hamNum++; printf(#%d: %s hamNum vertices[start]); for (j=0; j printf (->%s vertices[currentRoute[j]]); printf (costs %d
 cost); if (cost curMinCost =cost; curMinHamNum = hamNum; } }

Alan · Answer

Well 'start' will be rounded to 2 when it is passed as an argument to the findRoute and foundHamiltonian methods and vertices(2) is Chow Kit so that's why I think it's starting from there.

ana aly · Answer

Yes your result same as mine. Supposedly the start location is the KL Tower since I set the start value to 1.8 not the Chow Kit. The problem lies here and I am not sure what goes wrong.

Alan · Answer

I've been through the code and the only lines where I differed from yours were these: Public visited(VERTEXNUM - 1) As Integer Public currentRoute(VERTEXNUM - 1) As Integer You had an upper bound of VERTEXNUM for both of these arrays but it doesn't really matter as it won't make any difference to the results. I see that you've declared 'start' as a double but then assigned it to integer parameters which will force it to be rounded off. However if you don't do this then foundHamiltonian() is never called at all. These are the results I got when I ran it: #:1 Chow Kit->Bukit Bintang->China Town->Istana Negara->KL Tower->Chow Kitcosts 10.6 #:2 Chow Kit->Bukit Bintang->China Town->KL Tower->Istana Negara->Chow Kitcosts 12.9 #:3 Chow Kit->Bukit Bintang->Istana Negara->China Town->KL Tower->Chow Kitcosts 10.1 #:4 Chow Kit->Bukit Bintang->Istana Negara->KL Tower->China Town->Chow Kitcosts 13.9 #:5 Chow Kit->Bukit Bintang->KL Tower->China Town->Istana Negara->Chow Kitcosts 10.6 #:6 Chow Kit->Bukit Bintang->KL Tower->Istana Negara->China Town->Chow Kitcosts 12.1 #:7 Chow Kit->China Town->Bukit Bintang->Istana Negara->KL Tower->Chow Kitcosts 12.4 #:8 Chow Kit->China Town->Bukit Bintang->KL Tower->Istana Negara->Chow Kitcosts 12.9 #:9 Chow Kit->China Town->Istana Negara->Bukit Bintang->KL Tower->Chow Kitcosts 10.1 #:10 Chow Kit->China Town->Istana Negara->KL Tower->Bukit Bintang->Chow Kitcosts 12.1 #:11 Chow Kit->China Town->KL Tower->Bukit Bintang->Istana Negara->Chow Kitcosts 12.4 #:12 Chow Kit->China Town->KL Tower->Istana Negara->Bukit Bintang->Chow Kitcosts 13.9 #:13 Chow Kit->Istana Negara->Bukit Bintang->China Town->KL Tower->Chow Kitcosts 10.9 #:14 Chow Kit->Istana Negara->Bukit Bintang->KL Tower->China Town->Chow Kitcosts 12.4 #:15 Chow Kit->Istana Negara->China Town->Bukit Bintang->KL Tower->Chow Kitcosts 9.1 #:16 Chow Kit->Istana Negara->China Town->KL Tower->Bukit Bintang->Chow Kitcosts 10.6 #:17 Chow Kit->Istana Negara->KL Tower->Bukit Bintang->China Town->Chow Kitcosts 12.9 #:18 Chow Kit->Istana Negara->KL Tower->China Town->Bukit Bintang->Chow Kitcosts 12.9 #:19 Chow Kit->KL Tower->Bukit Bintang->China Town->Istana Negara->Chow Kitcosts 9.1 #:20 Chow Kit->KL Tower->Bukit Bintang->Istana Negara->China Town->Chow Kitcosts 10.1 #:21 Chow Kit->KL Tower->China Town->Bukit Bintang->Istana Negara->Chow Kitcosts 10.9 #:22 Chow Kit->KL Tower->China Town->Istana Negara->Bukit Bintang->Chow Kitcosts 10.1 #:23 Chow Kit->KL Tower->Istana Negara->Bukit Bintang->China Town->Chow Kitcosts 12.4 #:24 Chow Kit->KL Tower->Istana Negara->China Town->Bukit Bintang->Chow Kitcosts 10.6 lowest cost hamiltonian cycle: 15 w/ cost 9.1 It sounds like this may differ from what you got?

ana aly · Answer

Thank you for your reply. Actually I had changed the places and distances. The distance now involve decimal number so I use double as the data type. Therefore few changes had to be done in order to get the result in decimal also. No problem arise when number of places is 4 but once I add one more place and set the start value to the new location the output goes wrong. I plan to set until 15 locations. Here I attached the code. Public Class WebForm1 Inherits System.Web.UI.Page Public Const VERTEXNUM As Integer = 5 Public Const HUGE As Integer = 32000 Public Shared vertices() As String = {Bukit Bintang China Town Chow Kit Istana Negara KL Tower} 'distance in kilometre(s) Public Shared edges() As Double = {{0 0.9 2.1 3.1 1.8} {0.9 0 2.2 1.4 1.9} {2.1 2.2 0 3.4 1.6} {3.1 1.4 3.4 0 4.6} {1.8 1.9 1.6 4.6 0}} Public visited(VERTEXNUM) As Integer Public curMinCost As Double = HUGE Public curMinHamNum As Integer = 0 Public currentRoute(VERTEXNUM) As Integer Public Function main() As Double Dim start As Double = 1.8 Dim j As Integer For j = 0 To VERTEXNUM - 1 If (j start) Then findRoute(start j edges(start j) 0) End If Next j TextBox1.Text &= lowest cost hamiltonian cycle:  & curMinHamNum &  w/ cost  & curMinCost & Environment.NewLine Return 0 End Function Public Sub findRoute(ByVal start As Integer ByVal current As Integer ByVal costSoFar As Double ByVal numVisited As Integer) Dim j As Integer currentRoute(numVisited) = current If (current = start) Then If (numVisited = VERTEXNUM - 1) Then foundHamiltonian(start costSoFar + edges(current start)) End If Else visited(current) = 1 For j = 0 To VERTEXNUM - 1 If (visited(j) = 0) Then findRoute(start j costSoFar + edges(current j) numVisited + 1) End If Next j visited(current) = 0 End If End Sub Public Sub foundHamiltonian(ByVal start As Integer ByVal cost As Double) Dim j As Integer Static hamNum As Integer = 0 hamNum = hamNum + 1 TextBox1.Text &= #: & hamNum &   & vertices(start) For j = 0 To VERTEXNUM - 1 TextBox1.Text &= -> & vertices(currentRoute(j)) Next j TextBox1.Text &= costs  & cost & Environment.NewLine If (cost curMinCost = cost curMinHamNum = hamNum End If End Sub End Class As u can see the fist value in each curly bracket represent each location involve. When I set the start value to 1.8 the result display that the start location is China Town . I got confuse here and try to make changes here and there but it wont work. Maybe the data type that I used effect the way value passes along the functions.

Alan · Answer

As far as I can see you don't have anything hard-coded in there which would prevent the code from being generalized to cope with more than 4 vertices provided you change VERTEXNUM and the vertices and edges arrays appropriately. Also whilst I don't understand why you would want to change 'start' to a Double rather than an Integer I don't see that this would actually make any difference to the output because of VB.Net's numeric type coercion rules. Can you let me know what values you're using and what the output should be (as per the C program) and I'll take a look at it.

ana aly · Answer

i have a question here.i want to increase the number of location(vertexnum) involve to 15. firstly i up the number of location to 5. but the output doesnt show up. what should i change instead of the value of VERTEXNUM edges and vertices? for your information i had edit a little the code before. so maybe the data type caused this problem. i set the start location at this code Dim start As Double = 0 ... but when i set the start location to the 5th location the code doesnt work well. i had chaged the code everywhere but still not working. i assume this is because the data type i used...could you please help me on how to increase the number of location i can use

ana aly · Answer

i have a question here.i want to increase the number of location(vertexnum) involve to 15. firstly i up the number of location to 5. but the output doesnt show up. what should i change instead of the value of VERTEXNUM edges and vertices?

ana aly · Answer

Oh you are right Alan. I missed look the concatenate symbol at the function main. Thank you so much. It works.By the way there are so much more to learn :D

Alan · Answer

That's strange it should work OK :-/ Did you remember to concatenate each line to what's already in the TextBox's Text property (using the &= operator) as I did ? If you don't do that then it will overwrite it each time a line is written. The alternative would be to use the ListBox control.

ana aly · Answer

I had set the textmode to multiline but still it could not display all 7 lines of output. Is there any other way that could display the output?

Alan · Answer

Sorry I'm talking nonsense about the ASP.Net TextBox not being able to display multiple lines. You just need to set the TextMode property to TextBoxMode.MultiLine. I actually tested the revised code in a WinForms application where I needed to set the TextBox's Multiline property and change its dimensions to display all 7 lines. I then put the code back into a web form class as you had it but couldn't then find the Multiline property forgetting that things are done a little differently in ASP.Net :)

ana aly · Answer

So do you mean that even the textline is set to multiline but still it could not display all 7 lines? There might be a way at least could display the final result including the roads involved with the final result. Anyway thank you because finally it works

Alan · Answer

I've been through it all again and found a number of suble errors in the VB translation which were preventing it from working properly. The only problem with having a Web app rather than a Windows Forms app is that the former doesn't have a multiline TextBox and so can only show the final rather than all seven lines of output. Anyway here's the working version. I've stuck as closely as possible to the original C code and so I've set VERTEXNUM = 4 and got rid of the temporary variables: Public Class WebForm1 Inherits System.Web.UI.Page Private Sub Button1_Click( ByVal sender As System.Object ByVal e As System.EventArgs) Handles Button1.Click main() End Sub Public Function main() As Integer Dim start As Integer = 0 Dim j As Integer For j = 0 To VERTEXNUM - 1 If (j start) Then findRoute(start j edges(start j) 0) End If Next j TextBox1.Text = lowest cost hamiltonian cycle:  & curMinHamNum &  w/ cost  & curMinCost & Environment.NewLine 'changing line as follows will allow all 7 lines to be printed in WinForms application 'TextBox1.Text &= lowest cost hamiltonian cycle:  & curMinHamNum &  w/ cost  & curMinCost & Environment.NewLine Return 0 End Function Public Sub findRoute( ByVal start As Integer  ByVal current As Integer  ByVal costSoFar As Integer  ByVal numVisited As Integer ) Dim j As Integer currentRoute(numVisited) = current If (current = start) Then If (numVisited = VERTEXNUM - 1) Then foundHamiltonian(start costSoFar + edges(current start)) End If Else visited(current) = 1 For j = 0 To VERTEXNUM - 1 If (visited(j) = 0) Then findRoute(start j costSoFar + edges(current j) numVisited + 1) End If Next j visited(current) = 0 End If End Sub Public Sub foundHamiltonian( ByVal start As Integer  ByVal cost As Integer ) Dim j As Integer Static hamNum As Integer = 0 hamNum = hamNum + 1 TextBox1.Text &= #: & hamNum &   & vertices(start) For j = 0 To VERTEXNUM - 1 TextBox1.Text &= -> & vertices(currentRoute(j)) Next j TextBox1.Text &= costs  & cost & Environment.NewLine If (cost Then curMinCost = cost curMinHamNum = hamNum End If End Sub End Class

ana aly · Answer

Dear alan I had changed the code as your suggestion but still the output is not like what the C codes display Ø Is this because I make the project as web application but not windows application. Does this make any sense that cause the code doesn’t work? Ø the output that I try on the C code shows this #1: selandar->chinchin->jasin->merlimau->selandar costs 90 #2:… … Lowest cost Hamiltonian cycle: 2 w/ cost 85 Ø It seems like the calling procedures doesn’t work because the output I got after modification is this lowest cost hamiltonian cycle: 0 w/ cost 32000

Alan · Answer

I've compared the two and the main things I noticed are: 1. The vertices array should be of String rather than Char type. 2. Having changed the VERTEXNUM constant from 4 to 3 you've then overlooked this in some For statements and iterated up to 2 rather than 3. 3. You've tried to simplify some code within loops by assigning certain expressions to variables but have overlooked in some cases that the expressions depended on the loop variable itself. Here's what I think the corrected VB code should be: Public Class WebForm1 Inherits System.Web.UI.Page Public Const VERTEXNUM As Integer = 3 Public Const HUGE As Integer = 32000 Public Shared vertices() As String = {Selandar ChinChin Jasin Merlimau} ' changed Char to String Public Shared edges() As Integer = {{0 22 16 32} {22 0 15 26} {16 15 0 21} {32 26 21 0}} Public visited(VERTEXNUM) As Integer Public curMinCost As Integer = HUGE Public curMinHamNum As Integer = 0 Public currentRoute(VERTEXNUM) As Integer Private Sub Button1_Click(ByVal sender As System.Object ByVal e As System.EventArgs) Handles Button1.Click main() End Sub Public Function main() As Integer Dim start As Integer = 0 'Dim j As Integer ' not needed 'Dim x As Integer = edges(start j) 'not needed For j = 0 To 3 ' changed 2 to 3 If (j start) Then findRoute(start j edges(startj) 0) 'replaced x TextBox1.Text = lowest cost hamiltonian cycle:  & curMinHamNum &  w/ cost  & curMinCost 'several minor changes here Return 0 End If Next j End Function Public Sub findRoute(ByVal start As Integer ByVal current As Integer ByVal costSoFar As Integer ByVal numVisited As Integer) Dim j As Integer Dim w As Integer = numVisited + 1 Dim y As Integer = costSoFar + edges(current start) 'Dim z As Integer = costSoFar + edges(current j) 'not needed currentRoute(numVisited) = current If (current = start) Then If (numVisited = VERTEXNUM) Then ' removed -1 foundHamiltonian(start y) Else visited(current) = 1 For j = 0 To 3 ' changed 2 to 3 If (Not visited(j)) Then findRoute(start j costSoFar + edges(current j) w) 'replaced z End If Next j visited(current) = 0 End If End If End Sub Public Sub foundHamiltonian(ByVal start As Integer ByVal cost As Integer) Dim j As Integer Static hamNum As Integer = 0 hamNum = hamNum + 1 TextBox1.Text = #: & hamNum &   & vertices(start) ' changed  to   For j = 0 To 3 ' changed 2 to 3 TextBox1.Text = -> & vertices(currentRoute(j)) Next j 'TextBox1.Text = costs  & cost 'inserted space after costs If (cost curMinCost = cost curMinHamNum = hamNum End If End Sub End Class

ana aly · Answer

hi. here the codes that i translated. Public Class WebForm1 Inherits System.Web.UI.Page Public Const VERTEXNUM As Integer = 3 Public Const HUGE As Integer = 32000 Public Shared vertices() As Char = {Selandar ChinChin Jasin Merlimau} Public Shared edges() As Integer = {{0 22 16 32} {22 0 15 26} {16 15 0 21} {32 26 21 0}} Public visited(VERTEXNUM) As Integer Public curMinCost As Integer = HUGE Public curMinHamNum As Integer = 0 Public currentRoute(VERTEXNUM) As Integer Private Sub Button1_Click(ByVal sender As System.Object ByVal e As System.EventArgs) Handles Button1.Click main() End Sub Public Function main() As Integer Dim start As Integer = 0 Dim j As Integer Dim x As Integer = edges(start j) For j = 0 To 2 If (j start) Then findRoute(start j x 0) TextBox1.Text = lowest cost hamiltonian cycle: &  & curMinHamNum & cost &  & curMinCost Return 0 End If Next j End Function Public Sub findRoute(ByVal start As Integer ByVal current As Integer ByVal costSoFar As Integer ByVal numVisited As Integer) Dim j As Integer Dim w As Integer = numVisited + 1 Dim y As Integer = costSoFar + edges(current start) Dim z As Integer = costSoFar + edges(current j) currentRoute(numVisited) = current If (current = start) Then If (numVisited = VERTEXNUM - 1) Then foundHamiltonian(start y) Else visited(current) = 1 For j = 0 To 2 If (Not visited(j)) Then findRoute(start j z w) End If Next j visited(current) = 0 End If End If End Sub Public Sub foundHamiltonian(ByVal start As Integer ByVal cost As Integer) Dim j As Integer Static hamNum As Integer = 0 hamNum = hamNum + 1 TextBox1.Text = #: & hamNum &  & vertices(start) For j = 0 To 2 TextBox1.Text = -> & vertices(currentRoute(j)) Next j 'TextBox1.Text = costs & cost If (cost curMinCost = cost curMinHamNum = hamNum End If End Sub End Class

Jan Montano · Answer

Hi Ana Could you also please post your vb.net transalation? I guess from there we could figure out what's causing the unexpected behavior you're getting. We could check line by line if it really is the right translation. Cheers Jan