C ++ exception Article 2-Use of C ++ standard library exception classes

1 Inheritance Graph

2. Details

The root class in the C ++ standard library exception class hierarchy is exception, which is defined in the exception header file. It is the base class for all functions in the C ++ standard library to throw exceptions, the exception interface is defined as follows:

Namespace STD {

Class exception {

Public:

Exception () Throw (); // No exception is thrown

Exception (const exception & E) Throw ();

Exception & operator = (const exception & E) Throw ();

Virtual ~ Exception () Throw )();

Virtual const char * What () const throw (); // return the exception description

};

}

In addition to the exception class, C ++ also provides some classes for reporting Abnormal Program conditions. In the error models reflected in these predefined classes, it mainly includes two categories: logical errors and runtime errors.

Logical errors include invalid_argument, out_of_range, length_error, and domain_error. When the function receives an invalid real parameter, it will throw an invaild_argument exception. If the function receives a real parameter beyond the expected range, it will throw an out_of_range exception, and so on.

Namespace STD {

Class logic_error: Public exception {

Public:

Explicit logic_error (const string & what_arg );

};

Class invalid_argument: Public logic_error {

Public:

Explicit invalid_argument (const string & what_arg );

};

Class out_of_range: Public logic_error {

Public:

Explicit out_of_range (const string & what_arg );

};

Class length_error: Public logic_error {

Public:

Explicit length_error (const string & what_arg );

};

Class domain_error: Public logic_error {

Public:

Explicit domain_error (const string & what_arg );

};

}

Runtime errors are caused by events outside the program domain. They can only be detected at runtime, including range_error, overflow_error, and underflow_error. The function reports a Range Error in arithmetic operations by throwing range_eroor and an overflow error by throwing overflow_error.

Namespace STD {

Class runtime_error: Public exception {

Public:

Explicit runtime_error (const string & what_arg );

};

Class range_error: Public runtime_error {

Public:

Explicit range_error (const string & what_arg );

};

Class overflow_error: Public runtime_error {

Public:

Explicit overflow_error (const string & what_arg );

};

Class underflow_error: Public runtime_error {

Public:

Explicit underflow_error (const string & what_arg );

};

}

In addition, the bad_alloc exception is defined in the new header file. exception is also the base class of bad_alloc, which is used to report the situation where the new operator cannot properly allocate memory. When dynamic_cast fails, the program will throw the bad_cast exception class, which also inherits from the exception class.

Reprinted from: http://blog.csdn.net/zhq651/article/details/8425579

3. Example

# Include <stdexcept>

Try
{
Throw invalid_argument ("hah ");
// Throw out_of_range ("we get the outofrange error ");
} Catch (invalid_argument & in)
{
Cout <"we catch invalid_argument" <in. What () <Endl;
} Catch (...)
{
Cout <"we catch Unexpected error, exit" <Endl;
Return 1;
}