Exception Handling User-Defined Exception Classes

   

/*
A Programmer's Introduction to C# (Second Edition)
by Eric Gunnerson

Publisher: Apress  L.P.
ISBN: 1-893115-62-3
*/

// 04 - Exception HandlingUser-Defined Exception Classes
// copyright 2000 Eric Gunnerson
using System;

public class UserDefinedExceptionClasses
{
    public static void Main()
    {
        Summer summer = new Summer();
        try
        {
            summer.DoAverage();
        }
        catch (CountIsZeroException e)
        {
            Console.WriteLine("CountIsZeroException: {0}", e);
        }
    }
}
public class CountIsZeroException: ApplicationException
{
    public CountIsZeroException()
    {
    }
    public CountIsZeroException(string message)
    : base(message)
    {
    }
    public CountIsZeroException(string message, Exception inner)
    : base(message, inner)
    {
    }
}
public class Summer
{
    int    sum = 0;
    int    count = 0;
    float    average;
    public void DoAverage()
    {
        if (count == 0)
        throw(new CountIsZeroException("Zero count in DoAverage"));
        else
        average = sum / count;
    }
}