Treci zad 2 grupa

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

namespace Zad3
{
    class Program
    {
        struct Tacka
        {
            int x, y;
        }

        static double Povrsina(Tacka t1, Tacka t2, Tacka t3)
        {
            double a, b, c, p, o, s;
            a = Math.Sqrt(Math.Pow(t1.x - t2.x, 2) + Math.Pow(t1.y - t2.y, 2));
            b = Math.Sqrt(Math.Pow(t1.x - t3.x, 2) + Math.Pow(t1.y - t3.y, 2));
            c = Math.Sqrt(Math.Pow(t3.x - t2.x, 2) + Math.Pow(t3.y - t2.y, 2));
            o = a + b + c;
            s = o / 2;
            p = Math.Sqrt(s * (s - a) * (s - b) * (s - c));
            return p;
        }
        static void Main(string[] args)
        {
            Console.WriteLine("Unesi koordinate tacaka");
            double p;
            Tacka t1, t2, t3;
            t1.x = Convert.ToInt32(Console.ReadLine());
            t1.y = Convert.ToInt32(Console.ReadLine());
            t2.x = Convert.ToInt32(Console.ReadLine());
            t2.y = Convert.ToInt32(Console.ReadLine());
            t3.y = 0;
            t3.x = 0;
            p = Povrsina(t1, t2, t3);
            Console.Write("{0}", p);
            Console.ReadKey();
        }
    }
}