> double?

Also another couple of tips - if you want to assign a "double?" to a "double" you need to cast it, which may seem odd .. and if the value is null, you'll get an exception doing such a cast ... leading perhaps to code like this:

//function being called is defined as void DoSomething( double x )
double? myValue;
if( null !=  myValue )
{
   DoSomething( (double)myValue );
}

If you have a nullable value type like double? or int?, and want nulls to become a value in the equivalent non-nullable type, there is a shorthand you may come across:

double? myNullableValue; double myNonnullValue;
myNonnullValue = myNullableValue ?? 0;
// is equivalent to:
myNonnullValue = (myNullableValue!=null) ? (double)myNullableValue : 0;
// which is of course equivalent to
if(myNullableValue!=null) { myNonnullValue = (double)myNullableValue; }
else { myNonnullValue = 0; }

I wish the ?? syntax worked with strings, eg sValue??"None", but strings are objects, and it doesn't.

Walter