Segmentation Fault when trying to index an array of arrays of objects via a pointer

Can someone please tell me why I get a segmentation fault running this? I try and a pointer to an array of an array of objects, how I can fix this problem? The declaration of the sf::Vector2 class can be found here: http://www.sfml-dev.org/documentation/1.6/classsf_1_1Vector2.php

Many thanks.

#include <SFML/System/Vector2.hpp>
#include <iostream>
class Tet
{
    public:
        Tet();
   private:
        static sf::Vector2 <int> I[4];
        static sf::Vector2 <int> J[4];
        static sf::Vector2 <int> *types[2];

};

sf::Vector2 <int> Tet::I[4] = {sf::Vector2 <int>(0,1),
      开发者_如何学Python                         sf::Vector2 <int>(1,1),
                               sf::Vector2 <int>(2,1),
                               sf::Vector2 <int>(3,1)};

sf::Vector2 <int> Tet::J[4] = {sf::Vector2 <int>(1,1),
                               sf::Vector2 <int>(2,1),
                               sf::Vector2 <int>(3,1),
                               sf::Vector2 <int>(3,2)};

sf::Vector2 <int>* Tet::types[2] = { I,J };                                   

Tet::Tet()
{
    //trying to print out x member of first vector of I 
    std::cout << (*(*(types))).x << std::endl; 
}

main()
{
    Tet t = Tet();
}

EDIT: g++ compiler

You never allocate or instantiate the types array you are referencing. types is a pointer you can't assign concrete values to a nullptr which is how you left it at the moment.

Just declare it as an array instead of a pointer sf::Vector2<int> types[2][4];

You may want to consider a simpler more effective design perhaps by having a Vector2 object, a Matrix object, and then the Tet object which has a collection of matrices using STL containers and algorithms preferably.

maybe allocate types first and initialize with { &I, &J }