This document discusses exception handling in programming. It defines an exception as a problem that occurs during program execution, such as dividing by zero. It describes two types of exception handling: unstructured and structured. Unstructured handling uses if/else statements or On Error GoTo. Structured handling uses Try/Catch blocks with keywords like Try, Catch, Finally, and Throw to control program flow. It also shows exception class hierarchies and provides a code example using Try/Catch.
Definition and scope of exception handling in programming.
Definition and types of errors: Compile Time, Run Time, Syntactical, Logical errors.
Definition of exception handling and its purpose in program control flow.
Introduction to unstructured and structured exception handling methods. Two methods: 'On Error GoTo' and 'If...else' statements for unstructured handling.
Structured methods using Try, Catch, Finally, and Throw keywords, including VB.NET syntax.
Example code demonstrating structured exception handling with VB.NET.
Final slide thanking the audience for their attention.
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01
Text Title
Place yourown text
here
02 Exception
Handling
03
Unstructured Exception
Handling
04
Types of Exception
Handling
2
01 What is
Exception?
05 Structured Exception
Handling
EXCEPTION
An exception refersto a problem that arises
during program execution. It is brought about by
an unexpected circumstance. A good example is
when you are performing a division operation, and
then you divide by zero (0). An exception will be
raised.
5
Exception Handling
7
Exception handlingis the process of
responding to the occurrence,
during computation, of exceptions(
anomalous or exceptional conditions
requiring special processing ) often
disrupting the normal flow
of program execution.
On Error GoTo:
Public Class Form1
Dim num1 As Integer
Dim num2 As Integer
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles
Button1.Click
Dim result As Integer
On Error GoTo lbl
num1 = CInt(TextBox1.Text)
num2 = CInt(TextBox2.Text)
funA()
result = num1 num2
lbl:
MsgBox(result)
End Sub
13.
If…else :
Public ClassForm1
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles
Button1.Click
Dim array As Integer() = New Integer(3) {}
array(0) = 10
array(1) = 20
array(2) = 30
array(3) = 40
For i As Integer = 0 To array.Length - 1
MessageBox.Show(array(i))
Next
End Sub
End Sub
Structured Exception
Handling
15
With exceptionhandling, you can
transfer the control of a program from
one part to another.
In VB.NET, exceptions are handled in
Structured way using 4 keywords:
Keyword Detail
Try
The workof the Try block is to identify the code
block for which a specific exception will be
activated. It should be followed by a catch
block(s).
Catch
Catching of the Exception is done in this block. It
is an exception handler in which the Exception
is handled.
Finally
Use the Finally block to run a set of statements
whether an exception has occurred or not.
Throw
An exception is thrown after the occurrence of a
problem. This is the work of the Throw keyword.
18.
Syntax of Try/Catch
18
Try
[try_Statement(s) ]
[ Exit Try ]
[ Catch [ exception_name [ As type ] ] [ When expression ]
[ catch_Statement(s) ]
[ Exit Try ] ]
[ Catch ... ]
[ Finally
[ finally_Statement(s) ] ]
End Try
19.
Public Class Form1
Dimnum1 As Integer
Dim num2 As Integer
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles Button1.Click
Dim result As Integer
Try
num1 = CInt(TextBox1.Text)
num2 = CInt(TextBox2.Text)
funA()
result = num1 num2
Catch ex As DivideByZeroException
MsgBox(ex.Message)
Finally
MsgBox(result)
End Try
End Sub
Public Function funA() As Integer
Dim result As Integer
num1 = CInt(TextBox1.Text)
num2 = CInt(TextBox2.Text)
If num2 = 0 Then
Throw New DivideByZeroException("plz enter denominator greater then 0")
End If
result = num1 num2
End Function
End Class