c++ values not showing when printing 2d array in a "cout" function code example

Example: how to print a 2d array in c++

for (int i = 0; i < m; i++) 
{ 
   for (int j = 0; j < n; j++) 
   { 
      cout << arr[i][j] << " "; 
   } 
     
   // Newline for new row 
   cout << endl; 
}