Naming Array Elements, or Struct And Array Within a Union

Question

Consider the following struct:

struct Vector4D
{
   union
   {
      double components[4];
      struct { double x, y, z, t; } Endpoint;
   };
};
         


        

Answer 1

Padding bytes will not cause an issue as all variables are of type double. The compiler will treat Vector4D as a double array. That means, v.Endpoint.z is essentially the same as v[2].