Add new element and rearrange an array

[anhdung]

Hi alls,
I have an array of real number like as:
1.1 ; - 2.1 ; 3.1 ; - 1.0 ; 3.0 ; 5.1 ; 0.2 ; 0.5

Now, I want to insert two elements (1.1 ; 0.1) into the array right after third element. the elements before third element will insert the end of this array. The final array will be as:
1.1 ; 0.1 ; - 1.0 ; 3.0 ; 5.1 ; 0.2 ; 0.5 ; 1.1 ; - 2.1 ; 3.1

Could you please tell me how i can do this in VB6. Thank you very much.

[isnoend07]

I have a similar procedure i use, you can probably modify it to fit your needs:

Option Explicit
Private Declare Sub CopyMemory Lib "kernel32" Alias "RtlMoveMemory" (Destination As Any, Source As Any, ByVal Length As Long)

Private Sub Command1_Click()
Dim x() As Integer, y() As Integer
    Dim i As Integer, j As Integer
   
    ReDim x(1 To 3, 1 To 10)
   
        Debug.Print "Old array"
        For i = 1 To 3
            For j = 1 To 10
                x(i, j) = i * j
                Debug.Print i & " " & j & " " & x(i, j),
            Next
            Debug.Print
        Next
       
        Debug.Print "New array"
       
        ReDim y(1 To 4, 1 To 10)
       
       
        For i = 1 To 10
            CopyMemory y(1, i), x(1, i), 3 * 2
        Next
       
        For i = 1 To 4
             For j = 1 To 10
                Debug.Print i & " " & j & " " & y(i, j),
            Next
            Debug.Print
        Next


End Sub

[anhdung]

Thank you very much.

[westconn1]

here is another method

Sub addto(ByRef sarr() As String, narr() As String, pos As Integer)
tmp = sarr
j = UBound(narr)
ReDim sarr(UBound(sarr) + j + 1)
For i = 0 To UBound(narr)
    sarr(i) = narr(i)
Next
For i = pos To UBound(tmp)
    j = j + 1
    sarr(j) = tmp(i)
Next
For i = 0 To pos - 1
    j = j + 1
    sarr(j) = tmp(i)
Next
End Sub

call like

Dim strarr() As String, addarr() As String
mstr = "1.1 ; - 2.1 ; 3.1 ; - 1.0 ; 3.0 ; 5.1 ; 0.2 ; 0.5"
strarr = Split(mstr, ";")
addarr = Split("1.1; 0.1", ";")
addto strarr, addarr, 3

[anhdung]

Thank westconn1 very much. I modified your code for add new element in array of real number. It worked well.

I have a question about CopyMemory function, the first time I use this method.

Option Explicit

' Declare the memory copying funciton.
Private Declare Sub CopyMemory Lib "kernel32" Alias "RtlMoveMemory" (Destination As Any, Source As Any, ByVal Length As Long)

Private Sub Command1_Click()

Dim array1() As Single
ReDim array1(8) As Single

Dim array2() As Single
ReDim array2(10) As Single
Dim i As Long, j As Long, l As Long
Dim k As Long

For i = 1 To 8
      ReDim Preserve array1(i) As Single
      array1(i) = i
      List1.AddItem array1(i)
Next i

array2(1) = 0.1
array2(2) = 0.2

For j = 3 To 7
      CopyMemory array2(j), array1(j + 1), 4
Next j

For l = 8 To 10
     CopyMemory array2(l), array1(l - 7), 4
Next l


For k = 1 To UBound(array2) 
      List2.AddItem array2(k)
Next k

End Sub

I don't understand the use of ByVal Length As Long in CopyMemory. Could you please explain to me why you used 3 * 2 for your code.

In my code If i use ByVal Length As Long less than 4, new array will return an array like as 0.1 0.2 0 0 0 0 0 0 0 0

But I change ByVal Length As Long larger than 4, new array will return an array I want
0.1 0.2 4 5 6 7 8 1 2 3

[Milk]

If I may speak on behalf of isnoend07, the 3 is because there are 3 elements and the 2 is because each Integer element is 2 bytes long.

Be very careful with RtlMoveMemory (aka CopyMemory), as powerful as it is, it is not at all forgiving. One mistake will crash VB. If you do use it make sure you understand how VB holds it's variables in memory, and SAVE YOUR WORK before running the code.

There is also a small overhead associated with calling API making CopyMemory not so efficient for copying small amounts of Data.