How to avoid code duplication here?

Question

I have two flavours of a method in a class, one with an extra parameter

first one:

public override void CalcV(IV iv)
{
     initializations
     otherOperations

     for (int i=0; i < NUM; ++i)
     {
         SomeOtherOperations
         double v = GetV(a,b,c);
         SomeOtherOperationsUsing_v
     }

     restOfOperations
}

and second one:

public override void CalcV(IV iv, int index)
{
     initializations
     otherOperations

     for (int i=0; i < NUM; ++i)
     {
         SomeOtherOperations
         double v = GetV(a,b,c, index);
         SomeOtherOperationsUsing_v
     }

     restOfOperations
}

as you can see the only difference is that the first one calls GetV() with 3 parameters and the second one calls an overload of GetV() with 4 parameters.

How best I can avoid code duplication here?

Thanks!

Answer 1

If you're using .Net 4.0, you can make it an optional parameter:

public override void CalcV(IV iv, int index = -1)
{
    ....
    double v = index > -1 ? GetV(a,b,c, index) : GetV(a,b,c);

    ....
}