EXCEPTION HANDLING class 12th computer science.pptx

EXCEPTION HANDLING class 12th computer science.pptx

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  NAME OF TEACHER:MRS SUMAN VERMA, PGT(CS) DATE : July 24, 2024 CLASS AND SECTION / STREAM: XII A , Science Stream SUBJECT: Computer Science DETAILS OF TOPIC/SUB-TOPIC: Exception Handling TOTAL STUDENTS:06 PRESENT: ABSENT:
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  What you willlearn ??  Types of errors in Python  Concept of Syntax error  Concept of Exception  Types of Exception  How to handle exception  Applying the concept of Exception handling in making Python programs
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  Teaching Learning Outcomes- Will have the idea about types of exceptions during program execution  Students will be able to write Python code to handle various kind of exceptions during programming.
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  Exception in reallife?? In general – someone or something that is not included in a rule, group, or list, or that does not behave in the expected way
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  Error in Python Errorin Python can be of two types – Syntax errors and Exceptions. Syntax errors - Errors are problems in a program due to which the program will stop the execution. amount = 10000 if(amount > 2999) print("You are eligible to purchase Dsa Self Paced”):
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  Exceptions. Exceptions are raisedwhen the program is syntactically correct, but some internal events occur in the code which change the normal flow of the program. This error does not stop the execution of the program, however. Example: marks = 10000 b=0 a = marks / b print(a) Here in this code as we are dividing the ‘marks’ by zero so an error will occur known as ‘ZeroDivisionError’
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  Different types ofexceptions in python:  SyntaxError: This exception is raised when the interpreter encounters a syntax error in the code, such as a misspelled keyword, a missing colon, or an unbalanced parenthesis.  TypeError: This exception is raised when an operation or function is applied to an object of the wrong type, such as adding a string to an integer.  NameError: This exception is raised when a variable or function name is not found in the current scope.  IndexError: This exception is raised when an index is out of range for a list, tuple, or other sequence types.  EOFError: This exception is raised when end of file occurs during reading the content of file.  ZeroDivisionError: This exception is raised when an attempt is made to divide a number by zero.  ImportError: This exception is raised when an import statement fails to find or load a module.
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  Catching Exceptions with try– except – else - finally Statement – try: # Statements that can raise exceptions are kept inside the try clause except: # statements that handle the exception are written inside except clause. else: # This code executes if no exception finally: # This code always executes
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  OUTPUT- SOME EXAMPLES-
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  def fun(a): if a< 4: b = a/(a-3) print("Value of b = ", b) try: #fun(3) fun(5) except ZeroDivisionError: print("ZeroDivisionError Occurred and Handled") except NameError: print("NameError Occurred and Handled") else: print("Else block. No exception occurred") finally: print("Finally program executed") SOME EXAMPLES-
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   NameError Occurredand Handled  Finally program executed Output-
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   def fun(a): if a < 4:  b = a/(a-3)  print("Value of b = ", b)   try:  fun(3)  #fun(5)  except ZeroDivisionError:  print("ZeroDivisionError Occurred and Handled")  except NameError:  print("NameError Occurred and Handled")  else:  print("Else block. No exception occurred")  finally:  print("Finally program executed") SOME EXAMPLES-
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  Output-  ZeroDivisionError Occurredand Handled  Finally program executed
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  Advantages of ExceptionHandling: •Improved program reliability: By handling exceptions properly, you can prevent your program from crashing or producing incorrect results due to unexpected errors or input. •Simplified error handling: Exception handling allows you to separate error handling code from the main program logic, making it easier to read and maintain your code. •Cleaner code: With exception handling, you can avoid using complex conditional statements to check for errors, leading to cleaner and more readable code. •Easier debugging: When an exception is raised, the Python interpreter prints a traceback that shows the exact location where the exception occurred, making it easier to debug your code.
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  Disadvantages of ExceptionHandling: Performance overhead: Exception handling can be slower than using conditional statements to check for errors, as the interpreter has to perform additional work to catch and handle the exception. Increased code complexity: Exception handling can make your code more complex, especially if you have to handle multiple types of exceptions or implement complex error handling logic. Possible security risks: Improperly handled exceptions can potentially reveal sensitive information or create security vulnerabilities in your code, so it’s important to handle exceptions carefully and avoid exposing too much information about your program.
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  Recapitulation- Questions from Previousyear / CBSE Sample papers 1. When will the else part of try-except-else be executed? a) always b) when an exception occurs c) when no exception occurs d) when an exception occurs in to except block 2. When is the finally block executed? a) when there is no exception b) when there is an exception c) only if some condition that has been specified is satisfied d) always 3. State whether the following statement is True or False: An exception may be raised even if the program is syntactically correct 4. Which of the following statements is false? a) A try-except block can have more than one except statement b) One block of except statement cannot handle multiple exceptions c) The finally block is always executed d) When 1 == "1" is executed, no exception is raised
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  Just think !!
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  HOMEWORK- Write a programto count number of records in a binary file sports.dat by using the EOFError exception. The data is stored in the form of a list [id,name, gamename,state]
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  THANK YOU