Use Mid$ to Compose a Big String

 
    Const AllocFactor = 100000
    Dim S As String
    Dim S1 As String
    Dim tmp As String
    Dim i As Long
    Dim StrLen As Long
    Dim MaxLen As Long
    Dim Curpos As Long
    Dim CurLen As Long
    MaxLen = AllocFactor
    S = Space(MaxLen)
    Curpos = 1
    S1 = "abc"
    For i = 0 To 99999
        StrLen = Len(S1)
        CurLen = Curpos + StrLen - 1
        If CurLen > MaxLen Then
            tmp = S
            S = Space(MaxLen + AllocFactor)
            Mid$(S, 1, MaxLen) = tmp
            MaxLen = MaxLen + AllocFactor
        End If
        Mid$(S, Curpos, StrLen) = S1
        Curpos = CurLen + 1
    Next

    If CurLen < MaxLen Then S = Left$(S, CurLen)