// UsingExceptions.cs: Using finally blocks.
// finally blocks always execute, even when no exception occurs.
using System;

class UsingExceptions
{
    static void Main()
    {
        //
        // Case 1: No exceptions occur in called method
        //
        Console.WriteLine( "Calling DoesNotThrowException" );
        DoesNotThrowException();

        //
        // Case 2: Exception occurs and is caught in called method
        //
        Console.WriteLine( "\nCalling ThrowExceptionWithCatch" );
        ThrowExceptionWithCatch();

        //
        // Case 3: Exception occurs, but is not caught in called method 
        // because there is no catch block.
        //
        Console.WriteLine( "\nCalling ThrowExceptionWithoutCatch" );
       
        // call ThrowExceptionWithoutCatch
        try
        {
            ThrowExceptionWithoutCatch();
        }
        catch
        {
            Console.WriteLine( "Caught exception from " +
                                "ThrowExceptionWithoutCatch in Main" );
        }

        //
        // Case 4: Exception occurs and is caught in called method,
        // then rethrown to caller.
        //
        Console.WriteLine( "\nCalling ThrowExceptionCatchRethrow" );

        // call ThrowExceptionCatchRethrow
        try
        {
            ThrowExceptionCatchRethrow();
        }
        catch
        {
            Console.WriteLine( "Caught exception from " +
                                "ThrowExceptionCatchRethrow in Main" );
        }
    } // end method Main

    //
    // no exceptions thrown
    //
    static void DoesNotThrowException()
    {
        // try block does not throw any exceptions 
        try
        {
            Console.WriteLine( "In DoesNotThrowException" );
        }
        catch
        {
            Console.WriteLine( "This catch never executes" );
        }
        finally
        {
            Console.WriteLine( "finally executed in DoesNotThrowException" );
        }
        
        Console.WriteLine( "End of DoesNotThrowException" );
    } // end method DoesNotThrowException

    //
    // throws exception and catches it locally
    //
    static void ThrowExceptionWithCatch()
    {
        // try block throws exception
        try
        {
            Console.WriteLine( "In ThrowExceptionWithCatch" );
            throw new Exception( "Exception in ThrowExceptionWithCatch" );
        } // end try
        catch ( Exception exceptionParameter )
        {
            Console.WriteLine( "Message: " + exceptionParameter.Message );
        } // end catch
        finally
        {
            Console.WriteLine("finally executed in ThrowExceptionWithCatch" );
        } // end finally                                      

        Console.WriteLine( "End of ThrowExceptionWithCatch" );
    } // end method ThrowExceptionWithCatch

    //
    // throws exception and does not catch it locally
    //
    static void ThrowExceptionWithoutCatch()
    {
        // throw exception, but do not catch it
        try
        {
            Console.WriteLine( "In ThrowExceptionWithoutCatch" );
            throw new Exception( "Exception in ThrowExceptionWithoutCatch" );
        } // end try
        finally
        {
            Console.WriteLine( "finally executed in " +
                                "ThrowExceptionWithoutCatch" );
        } // end finally                              

        // unreachable code; logic error 
        Console.WriteLine( "End of ThrowExceptionWithoutCatch" );
    } // end method ThrowExceptionWithoutCatch

    // throws exception, catches it and rethrows it
    /// <summary>
    /// 
    /// <exception>AccountInvalidException</exception>
    /// <exception>AccountNotExistingException</exception>
    /// </summary>
    static void ThrowExceptionCatchRethrow()
    {
        // try block throws exception
        try
        {
            Console.WriteLine( "In ThrowExceptionCatchRethrow" );
            throw new Exception( "Exception in ThrowExceptionCatchRethrow" );
        } // end try
        catch ( Exception exceptionParameter )
        {
            Console.WriteLine( "Message: " + exceptionParameter.Message );
            
            // rethrow exception for further processing
            throw;

            // unreachable code; logic error
        } // end catch
        finally
        {
            Console.WriteLine( "finally executed in " +
                                "ThrowExceptionCatchRethrow" );
        } // end finally                              
        
        // any code placed here is never reached
        Console.WriteLine( "End of ThrowExceptionCatchRethrow" );
   }
}