class circularFree
{
public:
  bool testFree(int x);

  int freeCount();       // Returns TRUE iff x is free

  void allocate(int x);  // Allocates x.  Dies if not free.

  void freeUp(int x);    // x is made free.  Dies if not allocated.

  int allocateAny();     // Allocates some value that is available.

  circularFree(int n);

  ~circularFree();

private:
  int n,numberFree;
  int *prev,*next;
};