静态const数组double的静态const数组

Question

I managed to make an array of arrays of double s, having all of these static and const :

# myclass.h
class myclass {
    static constexpr double I_1[] = {... , ... , ... ...};
    static constexpr double I_2[] = {... , ... , ... ...};
    static constexpr double I_3[] = {... , ... , ... ...};
    ...

    static constexpr const double* list[] = {I_1,I_2,I_3,...};
}

Note that all arrays can have different sizes.

Now, this technique requires the definition of these static variables in the cpp file:

# myclass.cpp
constexpr const double* myclass::list[];
constexpr double myclass::I_1[], myclass::I_2[], myclass::I_3[],...

and this list can be very long if there are many arrays. This seems a little bit complicated to me.

Is there a better way?

Bonus question: is there a way to do it without requiring C++11?

Answer 1

This will provide what I believe OP is looking for.

In a header somewhere and no C++11 required

class ConfigDB
{
public:
    static const std::vector<std::vector<double>> db;

};

The cpp file allocating ConfigDB::db requires c++11 for the nifty initializer list.

const std::vector<std::vector<double>> ConfigDB::db
{
    {1,2,3,4},
    {5,6,7}
};

Non C++11 alternatives include loading all of the vector<double> s and then loading those into the vector<vector<double>> . As bad or Worse than OP's solution with the arrays.