c++ - How to define a 2D array of structures in the private parts of a class? -

i want define 2d array of structures in class in c++, how should it, here example approach struct tt

class swtlvn{ private: int a,b; tt yum[a][b]; }; 

can done in way? aos used member functions of class/ultimatey defined object cant defined inside member function. having defined externally going hassle no can do.

edit:

struct tt{ int a,b,c; tt(){} tt(int aa,int bb,int cc){a = aa; b = bb; c = cc;} }; 

without knowing more, should use similar to:

 class foo {  public:     foo(int _a, int _b) : a(_a), b(_b) {         yum.resize(a);         (size_t = 0; < a; i++) {            yum[i].resize(b);         }     }  typedef std::vector<std::vector<tt> > ttvector2d;  ttvector2d yum;  };