static void Main(string[] args) { var c = new calc(); System.Console.WriteLine(c.add(2, 3)); //5 System.Console.WriteLine(c.subtract(1, 3)); //-2 System.Console.WriteLine(c.multiply(13, 2)); System.Console.WriteLine(c.divide(13, 2)); var a = new int[] { 1, 5, 12, -2 }; System.Console.WriteLine(c.add(a)); //16 }