// filesdemo.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"
#include <iostream>
#include <fstream>

using namespace std;

const char* sourcefile = "f:\\Temp\\input.txt";

class Numbers {
	int n, k;
	int *data;
	int cstart, cend;
	bool isloaded;
public:
	Numbers();
	Numbers(const char*);
	void printRange(ostream& , const int , const int ) const; 
	void printData(ostream& ) const;
	void printFound(ostream& ) const;

	bool loadData(istream& ); 
	bool loadFile(const char* );

	bool getNext();
};

ostream& operator <<= (ostream& ostr, Numbers& num) {
	num.printFound(ostr);
	return ostr;
}

Numbers::Numbers() 
	: cstart(-1), cend(-1)  {

}

Numbers::Numbers(const char* fname) 
	: cstart(-1), cend(-1) {
	isloaded = loadFile(fname);

}

bool Numbers::loadFile(const char* name) {
	ifstream ifs(name);

	if (!ifs) {	// check if file was open  
		cout << " failed opening file " << endl;
		return false;
	}
	
	return loadData(ifs);
}
 
void Numbers::printRange(ostream& ostr, const int from, const int to) const {
	ostr << "[" << from << "," << to << "] : ";
	for (int i=from; i<to; i++)
		ostr << data[i] << ',';
	ostr << endl;
}

void Numbers::printFound(ostream& ostr) const {
	printRange(ostr, cstart, cend+1);
}

void Numbers::printData( ostream& ostr) const {
	printRange(ostr, 0, n);
}

// generic load data method
bool Numbers::loadData(istream& ifs) {
	int i = 0;

	// read n, k
	ifs >> n;
	ifs >> k;
	
	// allocate memory
	data = new int[n];


	// read integer values until EndOfFile is encountered
	// or feasible (n) number of values is retrieved

	while (! ifs.eof() && i < n) {
		ifs >> data[i++];
	}

	// have we read enough numbers
	if (i != n) 
		return false;
	
	return true;
}

bool Numbers::getNext() {
	cstart++;
	int sum = 0;
	cend = cstart;

	while (cend < n) {

		if (data[cend] > k) {
			cstart = ++cend;
			sum = 0;
			continue;
		}

		// while the current sum would overflow k 
		// when adding data[cend] - remove it
		while (sum + data[cend] > k) {
			sum -= data[cstart++];
		}

		// return true if match found
		if (sum + data[cend] == k) {
			return true;
		}

		sum += data[cend++];
	} 

	return false;
}

int main()
{
	Numbers nums(sourcefile);

	ofstream ofs("f:\\temp\\more.results.txt");
	while (nums.getNext()) {
		cout <<= nums;
		ofs <<= nums;
	};
}