TriangleArea

using System;

class SurfaceOfATriangle
{
    static double TriangleSurface(double side, double sideHeight)
    {
        double area = (side * sideHeight) / 2;
        return area;
    }
    static double TriangleSurface(double a, double b, double c)
    {
        double s = (a + b + c) / 2;
        double area = Math.Sqrt(s * (s - a) * (s - b) * (s - c));
        return area;
    }
    static double TriangleSurface(double a, double b, int angle)
    {
        double sin = Math.Sin((angle * Math.PI / 180));
        double area = (a * b * sin) / 2;
        return area;
    }

    static void Main()
    {
        Console.WriteLine("Hello! If you want to know any triangle's area, you are in the right place.");

        Console.WriteLine("You can choose which method to use.");
        Console.WriteLine("If you want to type in side and altitude choose method index '1'.");
        Console.WriteLine("If you want to type in three sides choose method index '2'.");
        Console.WriteLine("If you want to type in two sides and angle between them choose method index '3'.");
        Console.Write("Method index = ");
        int choice = int.Parse(Console.ReadLine());
        if (choice == 1)
        {
            Console.Write("Side = ");
            double side = double.Parse(Console.ReadLine());
            Console.Write("Altitude = ");
            double altitude = double.Parse(Console.ReadLine());
            double area = TriangleSurface(side, altitude);
            Console.WriteLine("The area of the triangle is " + area);
        }
        else if (choice == 2)
        {
            Console.Write("Side a = ");
            double a = double.Parse(Console.ReadLine());
            Console.Write("Side b = ");
            double b = double.Parse(Console.ReadLine());
            Console.Write("Side c = ");
            double c = double.Parse(Console.ReadLine());
            double area = TriangleSurface(a, b, c);
            Console.WriteLine("The area of the triangle is " + area);
        }
        else if (choice == 3)
        {
            Console.Write("Side a = ");
            double a = double.Parse(Console.ReadLine());
            Console.Write("Side b = ");
            double b = double.Parse(Console.ReadLine());
            Console.Write("Alpha = ");
            int alpha = int.Parse(Console.ReadLine());
            double area = TriangleSurface(a, b, alpha);
            Console.WriteLine("The area of the triangle is " + area);
        }
    }
}