Dealing with unexpected behaviour can be one of the most difficult parts in a system, even though there is so common, so we need a way to detect such behaviour as exceptions and handle it in a proper manner.
#include <iostream>
using namespace std;
void throwAnException(){
throw runtime_error("Runtime exception");
}
int main(){
try {
throwAnException();
} catch(runtime_error &rte){
cout << rte.what() << endl;
}
}
The type runtime_error is one of the standard library exception types. When what() is called a const char pointer is returned that points at a string that was passed into the constructor, in this case Runtime Exception
Standard Exception
The C++ Standard library provides a base class specifically designed to declare objects to be thrown as exceptions. It is called std::exception. This class has a virtual member function called what that returns a null-terminated character sequence (of type char *) and that can be overwritten in derived classes to contain some sort of description of the exception.
#include <iostream>
using namespace std;
class BusinessException : public exception {
public: virtual const char* what() const throw()
{
return "Business Exception";
}
};
void throwAnException(){
throw BusinessException();
}
int main(){
try {
throwAnException();
} catch(BusinessException &rte){
cout << rte.what() << endl;
}
}