Exception handling in C++ is used to manage and recover from unexpected errors or exceptional situations that might occur during program execution.
Try-Catch Blocks:
The try block is used to enclose the code that might cause an exception.
If an exception occurs within the try block, the program jumps to the nearest matching catch block.
Throwing Exceptions:
To indicate an error, you can “throw” an exception using the throw keyword.
Exceptions can be of any type, including standard library exceptions or user-defined types derived from std::exception.
Catching Exceptions:
The catch block is used to handle exceptions thrown within the corresponding try block.
You can catch exceptions by their types, including base classes, to handle related exceptions in a single block.
Usually, a reference (often const) to the exception type refers to the caught exception.
Standard Exceptions:
C++ provides a set of standard exception classes, such as std::runtime_error, std::logic_error, and std::invalid_argument, which are derived from std::exception.
Custom Exception Classes:
You can create your own exception classes by deriving them from std::exception or other existing exception classes.
Custom exception classes should typically provide a custom error message using the what() function.
Multiple Catch Blocks:
You can have multiple catch blocks to handle different types of exceptions.
Catch blocks are evaluated sequentially, and the first matching block is executed.
Order of Catch Blocks:
Place more specific catch blocks before more general ones. Specific exceptions should be caught before their base classes.
Unhandled Exceptions:
The program will terminate and display an error message if no catch block within the current scope is able to catch an exception.
Rethrowing Exceptions:
You can use the throw statement inside a catch block to rethrow the caught exception.
This allows an exception to be caught at one level of the call stack and then handled or rethrown at a higher level.
Resource Management:
Even during exceptions, use exception handling to release memory or close files.