Thou shalt not inherit from std::vector
Actually, there is nothing wrong with public inheritance of std::vector
. If you need this, just do that.
I would suggest doing that only if it is really necessary. Only if you can't do what you want with free functions (e.g. should keep some state).
The problem is that MyVector
is a new entity. It means a new C++ developer should know what the hell it is before using it. What's the difference between std::vector
and MyVector
? Which one is better to use here and there? What if I need to move std::vector
to MyVector
? May I just use swap()
or not?
Do not produce new entities just to make something to look better. These entities (especially, such common) aren't going to live in vacuum. They will live in mixed environment with constantly increased entropy.
The whole STL was designed in such way that algorithms and containers are separate.
This led to a concept of different types of iterators: const iterators, random access iterators, etc.
Therefore I recommend you to accept this convention and design your algorithms in such way that they won't care about what is the container they're working on - and they would only require a specific type of iterator which they'd need to perform their operations.
Also, let me redirect you to some good remarks by Jeff Attwood.
The main reason for not inheriting from std::vector
publicly is an absence of a virtual destructor that effectively prevents you from polymorphic use of descendants. In particular, you are not allowed to delete
a std::vector<T>*
that actually points at a derived object (even if the derived class adds no members), yet the compiler generally can't warn you about it.
Private inheritance is allowed under these conditions. I therefore recommend using private inheritance and forwarding required methods from the parent as shown below.
class AdVector: private std::vector<double>
{
typedef double T;
typedef std::vector<double> vector;
public:
using vector::push_back;
using vector::operator[];
using vector::begin;
using vector::end;
AdVector operator*(const AdVector & ) const;
AdVector operator+(const AdVector & ) const;
AdVector();
virtual ~AdVector();
};
You should first consider refactoring your algorithms to abstract the type of container they are operating on and leave them as free templated functions, as pointed out by majority of answerers. This is usually done by making an algorithm accept a pair of iterators instead of container as arguments.