using point;

​

namespace triangle

{

    struct TriangleType

    {

        public PointType a;

        public PointType b;

        public PointType c;

    }

​

    class Triangle

    {

        static Triangle _instance;

​

        static public Triangle instance

        {

            get

            {

                if (_instance == null)

                {

                    _instance = new Triangle();

                }

​

                return _instance;

            }

        }

​

        public TriangleType init()

        {

            TriangleType triangle;

            triangle.a = Point.instance.init();

            triangle.b = Point.instance.init();

            triangle.c = Point.instance.init();

            return triangle;

        }

​

        public double perimeter(TriangleType triangle)

        {

            return Point.instance.twoPointDistance(triangle.a, triangle.b) +

            Point.instance.twoPointDistance(triangle.b, triangle.c) +

            Point.instance.twoPointDistance(triangle.c, triangle.a);

        }

    }

}

​