Macro To Switch Between Header and Cpp File

Sub Jump()
'////////////////////////////////////////////
'Nooruddin Kapasi 1998.
'DESCRIPTION: Switch Between Header and cpp
'////////////////////////////////////////////
Dim myDocument
Dim a
Dim b
Dim Flag
Dim Flag1
Flag1 = 0
Flag = 1
a = ActiveDocument.FullName
tmp = InStr(a, ".cpp")
If tmp Then
        b = Left(a, Len(a) - 3) + "h"
        Flag1 = 1
Else
tmp = InStr(a, ".h")
If tmp Then
        b = Left(a, Len(a) - 1) + "cpp"
        Flag1 = 1
End If
End If
For Each myDocument In Application.Documents
    If myDocument.FullName = b Then
        myDocument.Active = True
        Flag = 0
        Exit For
        End If
Next
If Flag And Flag1 Then
        Documents.Open b, "Text"
End If
End Sub