Should a class validate itself or create another class to validate it?

Question

Let\'s say I have a class like:

class NavigationData
{
  float roll;
  float pitch;
  double latitude;
  double longitude;
}

and if I want to c

Answer 1

The right answer is: it depends.

The natural place to put such object logic is in the object itself. Sometimes though the validation rules could be dependent on a rules engine or some kind of larger "framework" which validates stuff. Another situation where you wouldn't want to do validation inside the object is when validation belongs in another tier, or layer or the application, such as the view layer.