#ifndef _DOCUMENTVECTOR_H_#define _DOCUMENTVECTOR_H_#include <iostream>#include <vector>#include <cmath>#include <string>class DocumentVector {	private:	int* frequencies; 	// TODO: using a vector instead of an array could be useful!	int size;	int num_words;	int max_word_index;	int min_word_index;	std::string identifier;		friend class DVReference;	class DVReference {	private:		DocumentVector &dv;		int index;				DVReference(DocumentVector &dv_, int index_) : dv(dv_), index(index_) {}		friend class DocumentVector;			public:				// cast to int		operator int () const		{			if (index >= dv.size)				return 0;			else				return dv.frequencies[index];		}		// preincrement operator	 	const DVReference& operator ++ () const		{			dv.add_word_index(index);			return *this;		}				// postincrement operator		int operator++ (int) const		{			int old_value = (int) (*this);			dv.add_word_index(index);			return old_value;		}		// += operator		const DVReference& operator += (unsigned int n) const 		{			dv.add_word_index(index, n);			return *this;		}	};	void add_word_index(int index, unsigned int n = 1) 	{		assert(index < size);		if(max_word_index < index) 			max_word_index = index;		if(min_word_index > index)			min_word_index = index;		if(frequencies[index] == 0 && n > 0)			num_words++;		frequencies[index]+= n;	}	public: 		// Default constructor	DocumentVector(int size_ = 0, std::string identifier_ = "unknown") :		frequencies(new int[size_]),		size(size_),		num_words(0),		max_word_index(0),		min_word_index(size),		identifier(identifier_)	{		for(int i = 0; i < size; i++)			frequencies[i] = 0;	}		// Copy constructor	DocumentVector(const DocumentVector &dv) :		frequencies (new int[dv.size]),		size (dv.size),		num_words (dv.num_words),		max_word_index (dv.max_word_index),		min_word_index (dv.min_word_index),		identifier(dv.identifier)	{		for(int i = 0; i < size; i++)			frequencies[i] = dv.frequencies[i];	}		// Destructor	~DocumentVector()	{		delete [] frequencies;	}		// Assignment operator	DocumentVector& operator = (const DocumentVector &dv)	{		if(this != &dv) {			delete [] frequencies;			frequencies = new int[dv.size];			size = dv.size;			num_words = dv.num_words;			max_word_index = dv.max_word_index;			min_word_index = dv.min_word_index;			identifier = dv.identifier;						for(int i = 0; i < size; i++)				frequencies[i] = dv.frequencies[i];		}		return *this;	}		int operator[](int index) const	{		if (index >= size)			return 0;		else			return frequencies[index];	}		DVReference operator[](int index)	{		return DVReference (*this, index);	}		// << and >> operators		friend std::ostream& operator << (std::ostream &os, const DocumentVector &dv)	{		os << dv.identifier;		os << ' ' << dv.size;		os << ' ' << dv.num_words;		os << ' ' << dv.min_word_index;		os << ' ' << dv.max_word_index;		for(int i = 0; i < dv.size; i++)			os << ' ' << dv[i];					return os;	}	friend std::istream& operator >> (std::istream& is, DocumentVector& dv) 	{		is >> dv.identifier;		is >> dv.size;		is >> dv.num_words;		is >> dv.min_word_index;		is >> dv.max_word_index;		dv.frequencies = new int[dv.size];		for(int i = 0; i < dv.size; i++)			is >> dv.frequencies[i];					return is;	}		// getters and setters	int get_max_word_index() const	{		return max_word_index;	}	int get_min_word_index() const	{		return min_word_index;	}	int get_num_words() const	{		return num_words;	}	 	std::string get_identifier() 	{		return identifier;	}};#endif /* _DOCUMENTVECTOR_H_ */