Lecture 09 Exception Handling(1 ) in c++.pptx
- 2. Exception Handling • Exceptions are errors that occur at runtime. • They are caused by a wide variety of exceptional circumstance, such as running out of memory, not being able to open a file, trying to initialize an object to an impossible value. • The process of handling these exceptions is called exception handling. • Using the exception handling mechanism, the control from one part of the program where the exception occurred can be transferred to another part of the code. • Using exception handling in C++, we can handle the exceptions so that our program keeps running.
- 3. Exception Handling • C++ provides an inbuilt feature for Exception Handling. • It can be done using the following specialized keywords: try, catch, and throw with each having a different purpose. try { // Code that might throw an exception throw SomeExceptionType("Error message"); } catch( ExceptionName e1 ) { // catch block catches the exception that is thrown from try block }
- 4. #include <iostream> #include <stdexcept> using namespace std; int main() { // try block try { int numerator = 10; int denominator = 0; int res; // check if denominator is 0 then throw runtime // error. if (denominator == 0) { throw runtime_error( "Division by zero not allowed!"); } // calculate result if no exception occurs res = numerator / denominator; //[printing result after division cout << "Result after division: " << res << endl; } // catch block to catch the thrown exception catch (const exception& e) { // print the exception cout << "Exception " << e.what() << endl; } return 0; } Output Exception Division by zero not allowed!
- 5. #include <iostream> using namespace std; int main() { int x = -1; // Some code cout << "Before try n"; // try block try { cout << "Inside try n"; if (x < 0) { // throwing an exception throw x; cout << "After throw (Never executed) n"; } } // catch block catch (int x) { cout << "Exception Caught n"; } cout << "After catch (Will be executed) n"; return 0; } Output Before try Inside try Exception Caught After catch (Will be executed)
- 6. Special Catch block • There is a special catch block called the ‘catch-all’ block, written as catch(…), that can be used to catch all types of exceptions.
- 7. #include <iostream> using namespace std; int main() { // try block try { // throw throw 10; } // catch block catch (char* excp) { cout << "Caught " << excp; } // catch all catch (...) { cout << "Default Exceptionn"; } return 0; } Output Default Exception
- 9. Standard Exception classes • Standard Exception Classes: • C++ provides several standard exception classes, such as std::runtime_error, std::logic_error, std::invalid_argument, etc., which can be used to represent different types of errors.
- 11. Practice Question • Write a C++ function named calculateSumOfSquares that takes three parameters of type int. The function should calculate the sum of squares of all the parameters if the following conditions are met: • All parameters are different. • All parameters are positive. • All parameters are odd. If any of these conditions are not met, the function should throw different exceptions: • If the parameters are not different, throw an exception with the message "Parameters must be different". • If any parameter is not positive, throw an exception with the message "Parameters must be positive". • If any parameter is not odd, throw an exception with the message "Parameters must be odd". In the main function: • Prompt the user to input three integers. • Call the calculateSumOfSquares function with the user-provided integers as arguments. • Handle any exceptions thrown by the function and display appropriate error messages. • If no exceptions are thrown, display the calculated sum of squares.
- 12. Exception Handling in classes
- 13. Exception Handling in classes • Consider Book chapter#14 example for Practice.