Can’t initialize array in C++ using const int value? [on hold]

I am making a text based game. I want to make a 2d array of ‘Rooms’ in my ‘GameWorld’ class.

I’m used to using C#, but am using C++ in order to learn it. The code I wrote I expected to work, but it gives error as shown in picture. If I write the figures 10 in each array container then it works.

#pragma once #include <string>  class GameWorld { public: GameWorld();   private: const int MAP_WIDTH = 10; const int MAP_HEIGHT = 10; Room Rooms[MAP_WIDTH][MAP_HEIGHT];  };  struct Room { Room(); std::string Name; std::string Description; std::string leftDescription; std::string rightDescription; std::string forwardDescription; std::string backDescription; //// TODO: Add up and down (potentially need a 3d array map, maybe too complex? //std::string upDescription; //std::string downDescription; }; 

enter image description here

Is it possible to create arrays this way using const? Or what is the correct way to make the array without hard-coding the size?