using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace Triunghi
{
    class punct
    {
        private double x, y; //campuri private, vor fi accesate prin proprietati
        public double X //proprietate de acces la data privata x
        {
            get
            {
                return x;
            }
            set
            {
                x = value;
            }
        }
        public double Y //proprietate de acces la data privata y
        {
            get
            {
                return y;
            }
            set
            {
                y = value;
            }
        }
        public punct() //constructor
        {
            x = 0; y = 0;
        }
        public punct(double a, double b) //constructor de initializare
        {
            x = a; y = b;
        }
        public punct(punct p) //constructor de copiere
        {
            x = p.x; y = p.y;
        }
        public void citire()//citire de la tastatura
        {
            Console.Write("x=");
            x = Int32.Parse(Console.ReadLine());
            Console.Write("y=");
            y = Int32.Parse(Console.ReadLine());
        }
        public void afis()//afisare pe ecran
        {
            Console.WriteLine("(" + x + "," + y+")");
        }

        public double dinst_la(punct b)
        {
            return Math.Sqrt((x - b.x) * (x - b.x) + (y - b.x) * (y - b.x));//folosesc date membru, nu proprietati
        }

    }

    class triunghi
    {
        public punct a, b, c; //3 puncte

        public triunghi()//constructor care foloseste constructorul de la clasa punct
        {
            a = new punct();
            b = new punct();
            c = new punct();
        }

        public triunghi(double x1, double y1, double x2, double y2, double x3, double y3)
        {//cosntructor de initializare
            a = new punct(x1,y1);
            b = new punct(x2, y2);
            c = new punct(x3, y3);
        }

        public triunghi(punct x, punct y, punct z)
        {// constructor de initializare care foloseste constructorul de copiere de la clasa punct
            a = new punct(x);
            b = new punct(y);
            c = new punct(z);
        }

        public void citire()// citire de la tastatura
        {
            a.citire(); b.citire();c.citire();
        }
        
        public void afis()// afisare pe ecran
        {
            a.afis(); b.afis(); c.afis();
        }

        private double dist(punct a, punct b)//distanta dintre 2 puncte, foloseste proprietatiel X si Y
        {//privata
            return Math.Sqrt((a.X - b.X) * (a.X - b.X) + (a.Y - b.Y) * (a.Y - b.Y));
        }

        public double perimetru()//petrimetrul triunghiului
        {
            return dist(a, b) + dist(b, c) + dist(c, a);
        }

        public double aria()// aria triunghiului
        {
            double p = perimetru() / 2;
            double B = dist(a, c);
            double A = dist(b, c);
            double C = dist(a, b);
            return Math.Sqrt(p*(p-A)*(p-B)*(p-C));
        }

    }

    class Program
    {
        static void Main(string[] args)
        {
            triunghi t = new triunghi();// apel constructor triunghi
            triunghi t2 = new triunghi(1, 1, 3, 4, 0, 6);//apel constructor triunghi cu 6 valori reale
            punct x, y, z;
            x = new punct(0, 0);// apel constructor punct pt initializare
            y = new punct(3, 6);
            z = new punct(2, 1);
            triunghi t3 = new triunghi(x, y, z);//apel constructor de initializare cu 3 puncte
            t.citire();
            t.afis();
            t2.afis();
            t3.afis();
            Console.WriteLine(t2.perimetru());
            Console.WriteLine(t2.aria());
            Console.WriteLine(t3.perimetru());
            Console.WriteLine(t3.aria());
            Console.WriteLine(x.dinst_la(y));
            Console.ReadLine();
        }
    }
}