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Standard exception class
Base class for standard exceptions.
All objects thrown by components of the standard library are derived from this class. Therefore, all standard exceptions can be caught by catching this type.
It is declared as:
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class exception {
public:
exception () throw();
exception (const exception&) throw();
exception& operator= (const exception&) throw();
virtual ~exception() throw();
virtual const char* what() const throw();
}
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Some classes derived from exception are: bad_alloc, bad_cast, bad_exception, bad_typeid, logic_error, runtime_error, ios_base::failure...
Members
- default constructor: exception () throw();
- Constructs an object.
- copy constructor: exception (const exception&) throw();
and assignment: exception& operator= (const exception&) throw();
- Copies an exception object (the results of calling member what on the copy are implementation-specific).
- destructor: virtual ~exception() throw();
- Destroys the object.
- const char* what() const throw();
- Returns a null terminated character sequence containing a generic description of the exception.
Both the wording of such description and the character width are implementation-defined.
Example
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// exception example
#include <iostream>
#include <typeinfo>
using namespace std;
class Polymorphic {virtual void Member(){}};
int main () {
try
{
Polymorphic * pb = 0;
typeid(*pb); // throws a bad_typeid exception
}
catch (exception& e)
{
cerr << "exception caught: " << e.what() << endl;
}
return 0;
}
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Possible output:
exception caught: St10bad_typeid
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