Extract the value of interest rows and copy that to new Mat

Extract the value of interest rows and copy that to new Mat.cpp

cout << "origin\n";
	Mat a = (Mat_<int>(5, 5) << 1, 2, 3, 4, 5,
		7, 8, 9, 10, 11,
		12, 13, 14, 15, 16,
		17, 18, 19, 20, 21,
		22, 23, 24, 25, 26);
	cout << a << endl;

	cout << "\ninterest index of row - 0,3\n";
	vector< int> row_index_interest;
	row_index_interest.push_back(0);
	row_index_interest.push_back(3);

	cout << "\ncopy interest rows to new Mat\n";
	Mat b;
	for (auto it: row_index_interest)
	{
		cout << a.row(it) << endl;
		b.push_back(a.row(it));
	}

	cout << "\nnew Mat\n";
	cout << b << endl;