Default initialisations

Author: tturocy

src/games/game.h

@@ -602,13 +602,13 @@ class CartesianProductSpace {
 
 class CartesianSubset {
 public:
-  const CartesianProductSpace *m_space;
+  const CartesianProductSpace *m_space{nullptr};
   std::vector<std::vector<int>> m_allowedDigits;
 };
 
 template <class T> class CartesianTensor {
 public:
-  const CartesianProductSpace *m_space;
+  const CartesianProductSpace *m_space{nullptr};
   std::vector<T> m_data;
 };