Handling Exceptions in C#
By J.V.Ravichandran

Exceptions are errors that may occur during the run-time of a program. Exception handling, thus, becomes an integral part of programming. In C#, exceptions are handled via the Exception base class. You can also create your own Exception class but, which will, necessarily, derive from the base, inbuilt Exception class.

An exception is, for example, a "divide by zero operation", which will result in a faulty or a needless result and hence, needs to be handled in a program. An exception can also be, "IndexOutOfBounds", which arises out when your program tries to access a non-existent element in an array say, 101, in an array of max size 100. There are many such inbuilt exceptions that are handled by the Exception base class but, since logic is about possibilities, the possibility of an unhandled exception may arise and to know how to create your own exception class to handle such a calamity is the purpose of this article.

The following is a program that defines my own Exception class.

using System;
public class MyException:Exception
{
public string s;
public MyException():base()
{
s=null;
}
public MyException(string message):base()
{
s=message.ToString();
}
public MyException(string message,Exception myNew):base(message,myNew)
{
s=message.ToString();// Stores new exception message into class member s
}
public static void Test()
{
string str,stringmessage;
bool flag=false;
stringmessage=null;
char ch=' ';
int i=0;
Console.Write("Please enter some string (less than 27 characters) - ");
str=Console.ReadLine();
try{
ch=str[i];
while (flag==false)
{
if (ch=='\r')
{
flag=true;
}
else{
ch=str[i];
i++;
}
}
}
catch(Exception e){
flag=true;
}

if (i>27)
{
stringmessage="You cannot enter more than 27 characters !";
throw new MyException(stringmessage);
}
}
public static void Main()
{
try
{
Test();
}
catch(MyException e)
{
Console.WriteLine(e.s);
}
}
}