Public Default Property Item( _
   ByVal index As Integer _
) As Double

Dim instance As Vector
Dim index As Integer
Dim value As Double
 
instance.Item(index) = value
 
value = instance.Item(index)

public double this( 
   int index
) {get; set;}

public:
property double default [int] {
   double get(intindex);
   void set (intindex, doublevalue);
}