text: /* File : example.h */
  
  class Vector {
  private:
    double x,y,z;
  public:
    Vector() : x(0), y(0), z(0) { }
    Vector(double x, double y, double z) : x(x), y(y), z(z) { }
    friend Vector operator+(const Vector &a, const Vector &b);
    char *as_string();
  };
  
  class VectorArray {
  private:
    Vector *items;
    int     maxsize;
  public:
    VectorArray(int maxsize);
    ~VectorArray();
    Vector &operator[](int);
    int size();
  };
  