std::exception::exception
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                    | exception(); | (1) | |
| exception( const exception& other ); | (2) | |
Constructs new exception object.
1) Default constructor. what() returns empty string.
2) Copy constructor. Initializes the contents with those of 
otherParameters
| other | - | another exception to assign the contents of | 
Exceptions
| (none) | (until C++11) | 
| noexcept specification:   noexcept | (since C++11) | 
Notes
Because copying std::exception is not permitted to throw exceptions, when derived classes (such as std::runtime_error) have to manage a user-defined diagnostic message, it is typically implemented as a copy-on-write string.