static void Main(string[] args)
        {
            int squareheight,area,perimeter;
            Console.Write("What is the height of your square? :");
            squareheight = Convert.ToInt32(Console.ReadLine());
            area = squareheight * squareheight;
            perimeter = 4 * squareheight;
            Console.WriteLine("Area : {0}\nPerimeter : {1}",area,perimeter); //   "\n"--> new line
            Console.ReadKey();
        }