Question

I am trying to initialize a multidimensional array. Here is my syntax; this does not create errors but it does not store all values either. Although it correctly prints out all records in this snippet,

        dFirstWeek = CDate(FirstWeek)
        dFirstWeek = DateAdd(DateInterval.WeekOfYear, -1, dFirstWeek)

        Dim dFirstDay As Date
        Dim arrWeekYear(5000, 1) As Date
        Dim i As Integer = 0
        Dim j As Integer = 0
        dFirstDay = dFirstDay.AddDays(1)

        While dFirstWeek <= dLastWeek
            dFirstDay = dFirstWeek
            dFirstWeek = dFirstWeek.AddDays(7)

            While dFirstDay < dFirstWeek
                arrWeekYear(i, j) = (dFirstWeek)
                arrWeekYear(i, j + 1) = (dFirstDay)

                Response.Write(arrWeekYear(i, j).ToString("d"))
                Response.Write("           ;")
                Response.Write(arrWeekYear(i, j + 1).ToString("d"))
                Response.Write("<br>")
                dFirstDay = dFirstDay.AddDays(1)
                j = 0
            End While
            i = i + 1
        End While

later in this code, I try to reprint this array as follows:

            i = 0
            j = 0
            Dim k As Integer = 0
            'Response.Write(arrWeekYear.GetLength(0))

            While k < arrWeekYear.GetLength(0) - 2
                Response.Write(arrWeekYear(i, j).ToString("d"))
                Response.Write("           ;")
                Response.Write(arrWeekYear(i, j + 1).ToString("d"))
                Response.Write("<br>")
                j = 0
                i = i + 1
                k = k + 1
            End While

but this time, only one “j” record appears per “i” record. Why is this? And then after these few records, many dates resembling null dates appear: “1/1/0001 “

So why do all records appear in upper section, but not from lower? Did I insert values wrongly into this array? And it does not have to have fixed number of rows, just a fixed number of columns.

Answer 1

Dim arrWeekYear(5000, 1) As Date

That’s a multi-dimensional array all right, but the second dimension only has a size of 2! And you access it via j, which is always 0 in your code. That makes no sense. Is that really what you want? I suggest you use a data structure inside your array instead of a multi-dimensional array.

In fact, you almost never want to use a multi-dimensional array. At all. Complex objects are almost always more appropriate. The only real exception is when you actually want to store a mathematical matrix.