User defined exception example with power of a number demo in C#

Below is the code which takes two parameters x and y and it calculates the power of a number(x raise to y). If we pass y as a negative number as an argument it will throw a user defined exception. For this we have created a class which inherits an "exception" superclass and it contains an overriden tostring() method to print the user defined exception message.


using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Exception_inheritance_demo_2
{
    class MyEx : Exception
    {
        public override string ToString()
        {
            return "Negative number not allowed";
        }

    }
    class A
    {
        void pow(int x, int y)
        {
            if (y < 0)
                throw new MyEx();
            else
            {
                int z = 1;
                while (y > 0)
                {
                    z = z * x;
                    y--;
                }

                Console.WriteLine("Power={0}",z);
            }
        }

        static void Main(string[] args)
        {
            A a1 = new A();
            try
            {
                a1.pow(4,2);
                a1.pow(-4,-1);
                a1.pow(3,3);
            }
            catch (Exception ex)
            {
                Console.WriteLine("{0}", ex.ToString());
            }
            Console.ReadLine();
        }
    }

}