template <class vector>

struct HeadLocation{

	vector x;

	vector y;

};

vector<HeadLocation<int> > gt_loc_;  //二维vector容器

void ReadLocationFromTextFile(const string filename) {

	cout << "Opening file " << filename << endl;

	ifstream infile(filename.c_str());

	if (!infile){ printf("不存在此文本文件！"); };

	int num_crowd;

	infile >> num_crowd;

	if (num_crowd <= 0){ cout << "Number of crowd must be positive!\n"; };

	gt_loc_.clear(); //size = 0, capicity =?

	gt_loc_.resize(num_crowd); //size = num_crowd（行）

	for (int i = 0; i < num_crowd; i++) {

		/*HeadLocation<float> location_t;

		HeadLocation<int> location(location_t.begin(), location_t.end());*/

		HeadLocation<int> location;

		infile >> location.x >> location.y;

		for (int j = 0; j < 3; ++j) {

			location.x = (location.x - 1) / 2;

			location.y = (location.y - 1) / 2;

		}

		gt_loc_[i] = location;

	}

	infile.close(); // 关闭文件

}