#ifndef _COLLECTION_H_
#define _COLLECTION_H_

class Collection
{
  public:
    virtual ~Collection() {}

    virtual void add(int) = 0;
    virtual bool remove(int) = 0;
    virtual Collection& operator=(const Collection&) = 0;
    virtual int operator[](int) = 0;
    virtual Collection *copy(void) = 0;

    int get_size(void) const;
    void iterate(void (*)(int *));
    virtual bool contains(int) const;

  private:
  protected:
    Collection() : size_(0) {}
    int size_;
};

#endif