vector holding read-only matrices?

I want to use a vector to hold read-only integer-matrices of the size 5x5

vector<const int[5][5]> startingPieces;

But this declaration causes a bunch of weird errors I've never ever seen before.

error C2535: 'const int (*std::allocator<_Ty>::address(const int (&)[5][5]) const)[5][5]' : member function already defined or declared
1>        with
1>        [
1>            _Ty=const int [5][5]
1>        ]
1>        c:\program files\microsoft visual studio 9.0\vc\include\xmemory(109) : see declaration of 'std::allocator<_Ty>::address'
1>        with
1>        [
1>            _Ty=const int [5][5]
1>        ]
1>        c:\program files\microsoft visual studio 9.0\vc\include\vector(429) : see reference to class template instantiation 'std::allocator<_Ty>' being compiled开发者_Python百科
1>        with
1>        [
1>            _Ty=const int [5][5]
1>        ]
1>        c:\program files\microsoft visual studio 9.0\vc\include\vector(439) : see reference to class template instantiation 'std::_Vector_val<_Ty,_Alloc>' being compiled
1>        with
1>        [
1>            _Ty=const int [5][5],
1>            _Alloc=std::allocator<const int [5][5]>
1>        ]
1>        c:\users\eric\documents\visual studio 2008\projects\testing grounds\testing grounds\main.cpp(14) : see reference to class template instantiation 'std::vector<_Ty>' being compiled
1>        with
1>        [
1>            _Ty=const int [5][5]
1>        ]

So, what is wrong with this declaration?

Two things - firstly vectors cannot hold const objects - see Can I use const in vectors to allow adding elements, but not modifications to the already added? for a discussion of this. And secondly they cannot hold arrays, as the things they hold must be copyable and assignable, and arrays are neither.

What you should do here is create your own matrix class that stores the 5x5 array of data and then create your vector with that.

One option is to use the array class (your implementation may support std::array or std::tr1::array; if not, you can use boost::array from the Boost libraries):

std::vector<std::array<std::array<int, 5> > >

The elements stored in the container still cannot be const; you can make the entire vector const if that works for your use case.