namespace Class_make
{
    interface Polygon
    {
       
     public int Area(int a, int b);
     
    }

    class Square : Polygon
    {
     public int Area(int a,int b)
      {
          Console .WriteLine ("직사각형 면적");
          return a * b ;
      }
   
    }
    class Triangle : Polygon
    {
        double Area(int a, int b)
        {
            Console.WriteLine("삼각형 면적");
            return a * b / 2;

        }
    }
  

 

    class Program
    {
        static void Main(string[] args)
        {
            Polygon  p1 = new Triangle ();
            p1.Area(5,4);

            Polygon p2 = new Square();
            p2.Area(6,7);

          

        }
    }
}