SurfaceOfTriangle

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

namespace _4.SurfaceOfTriangle
{
    /*Write methods that calculate the surface of a triangle by given:
Side and an altitude to it; Three sides; Two sides and an angle between them. Use System.Math.*/
    class Program
    {
        static void SOfTriangle1(int a, int ha)
        {
            double s = a * ha / 2.0;
            Console.WriteLine("The surface of the triangle is {0}", s);
        }
        static void SOfTriangle2(int a, int b, int c)
        {
            double p = (a + b + c) / 2.0;
            double s = Math.Sqrt(p * (p - a) * (p - b) * (p - c));
            Console.WriteLine("The surface of the triangle is {0}", s);//neto4nost (5,2,6)
        }
        static void SOfTriangle3(int a, int b, double c)
        {
            double angle = Math.PI * c / 180.0;
            double s = a * b * Math.Sin(angle) / 2;
            Console.WriteLine("The surface of the triangle is {0}", s);
        }

        static void Main(string[] args)
        {
            Console.WriteLine("What do we have? \n a)Side and an altitude to it \n b)Three sides \n c)Two sides and an angle between them");
            string choise = Console.ReadLine();
            if (choise == "a")
            {
                Console.WriteLine("the side is:");
                int a = int.Parse(Console.ReadLine());
                Console.WriteLine("the altitude to it is:");
                int ha = int.Parse(Console.ReadLine());
                SOfTriangle1(a,ha);
            }
            else if (choise == "b")
            {
                Console.WriteLine("the first side is:");
                int a = int.Parse(Console.ReadLine());
                Console.WriteLine("the second side is:");
                int b = int.Parse(Console.ReadLine());
                Console.WriteLine("the third side is:");
                int c = int.Parse(Console.ReadLine());
                SOfTriangle2(a,b,c);
            }
            else if (choise == "c")
            {
                Console.WriteLine("the first side is:");
                int a = int.Parse(Console.ReadLine());
                Console.WriteLine("the second side is:");
                int b = int.Parse(Console.ReadLine());
                Console.WriteLine("the angle between them is:");
                double c = double.Parse(Console.ReadLine());
                SOfTriangle3(a, b, c);
            }
            else Console.WriteLine(" Invalid option!");
        }
    }
}