Exception Handling

Exception Handling in C++ is a process to handle runtime errors. We perform exception handling so the normal flow of the application can be maintained even after runtime errors.

In C++, exception is an event or object which is thrown at runtime. All exceptions are derived from std::exception class. It is a runtime error which can be handled. If we don’t handle the exception, it prints exception message and terminates the program.


Advantage

It maintains the normal flow of the application. In such case, rest of the code is executed even after exception.


C plus plus Exception Classes

In C++ standard exceptions are defined in <exception> class that we can use inside our programs. The arrangement of parent-child class hierarchy is shown below:

 


 

All the exception classes in C++ are derived from std::exception class. Let’s see the list of C++ common exception classes.

ExceptionDescription
std::exceptionIt is an exception and parent class of all standard C++ exceptions.
std::logic_failureIt is an exception that can be detected by reading a code.
std::runtime_errorIt is an exception that cannot be detected by reading a code.
std::bad_exceptionIt is used to handle the unexpected exceptions in a c++ program.
std::bad_castThis exception is generally be thrown by dynamic_cast.
std::bad_typeidThis exception is generally be thrown by typeid.
std::bad_allocThis exception is generally be thrown by new.

 Exception Handling Keywords

In C plus plus, we use 3 keywords to perform exception handling:

  • try
  • catch, and
  • throw