basic use of arrays

Question

I'm having a problem with a project I'm attempting to create and was wondering if someone could help me. I'm trying to create a sudoku-like game and am only stumped when it comes to displaying incorrect user responses. I've attempted to use an array to store values of button.text numbers with incorrect responses, but don't know how to vary the length of the array depending on the number they answer incorrectly.

If Integer.Parse(btn1.Text) <> answers(0) Then

numberwrong += 1

btn1.BackColor = Color.Red

btn1check = True

wronganswer(0) = 1

This is an example of a code block that'll check every square. The wronganswer array is where I was hoping to store my incorrect answers. I've been instructed to simply put a msgbox within the if statement that checks each square. If the user were to answer all 81 boxes incorrectly, there'd be 81 message windows open and I'm not one to swamp my users in that fashion. Is there a way to redim the array by the number of another variable in a way like:

ReDim wronganswer(numberwrong)

so I have wronganswer() with the numberwrong number of dimensions? Even if I can figure out how to do that, is there a way to dynamically reproduce that in the msgbox for which buttons are actually incorrect?

Alan · Answer

As Mike said you need to concatenate the wrong answers into a single string before calling the Msgbox function. If wrongAnswer is your ArrayList then try this: Dim squares As String =  Dim answer As Integer Dim count As Integer = wrongAnswer.Count wrongAnswer.Sort ' omit this line if sorting not needed For i As Integer = 1 To count answer = DirectCast(wrongAnswer(i - 1) Integer) squares &=   + answer.ToString If i = Count Then Exit For If i Mod 9 0 Then squares &=  Else squares &= Chr(13) End If Next i MsgBox(You need to check these squares :  & Chr(13) & Chr(13) & squares)

keith wood · Answer

I've definitely considered writing it all to one message box that's what I wish I could figure out how to do. The use of the arraylist helps a lot and that'll let me dynamically add the values I need to the array. How though do I display that in a message box? I've attemped scenarios like: MsgBox( You need to check  & wronganswer() & . ) MsgBox( You need to check  & wronganswer.ToString & . ) 'this successfully outputs the array type I looked up more information on this subject and found a great tutorial on how to output this to a console app but considering that's not what I have to work with it won't help me. Since I can't run an If or For statement within a MsgBox I'm stumped. I know this s probably really basic for your forum and I thank you for your patience.

Mike Gold · Answer

You may want to use an ArrayList instead of an array. This way you can grow and shrink the array dynamically. Is this what you are asking? I suspect you are asking how to keep track of wrong answers in the sudoku grid? Definitely try not to use GUI components to represent a part of your array. You should keep the grid stored in memory. (e.g. Dim SudokuBoardAnswers(99) As Integer) Initialize the grid to 0 and if someone has a wrong answer put it in the correct location in the rectangular array. Also as you said you definitely don't want to pop up 81 message boxes. Consider writing all the wrong answers to a string and then putting it in the message box. Loop through the wrong answer grid and concatenate the wrong answers to the string.