static void Main(string[] args)
{
triangle ABC = new triangle(3, 4, 5);
Console.WriteLine("Triangle with sides 3,4,5");
Console.WriteLine("Perimeter of ABC is " + ABC.getPerimeter());
Console.WriteLine("Area of ABC is " + ABC.getArea());
rectangle A = new rectangle();
A.setHeight(5);
A.setLength(12);
Console.WriteLine("Perimeter of rectangle A is " + A.getPerimeter());
Console.WriteLine("Area of rectange A is " + A.getArea());
}