/// <summary>
/// Performs an "exclusive-or" of the two sets, keeping only the elements that
/// are in one of the sets, but not in both. The original sets are not modified
/// during this operation. The result set is a <c>Clone()</c> of one of the sets
/// (<c>a</c> if it is not <c>null</c>) containing
/// the elements from the exclusive-or operation.
/// </summary>
/// <param name="a">A set of elements.</param>
/// <param name="b">A set of elements.</param>
/// <returns>A set containing the result of <c>a ^ b</c>. <c>null</c> if both sets are <c>null</c>.</returns>
public static Set ExclusiveOr(Set a, Set b)
{
if (a == null && b == null)
{
return(null);
}
else if (a == null)
{
return((Set)b.Clone());
}
else if (b == null)
{
return((Set)a.Clone());
}
else
{
return(a.ExclusiveOr(b));
}
}
