Method Trouble

Examples/NoModules/Chapter 16/Ex16_05/Troubles.h:10–12

{
public:
  explicit Trouble(std::string_view message = "There's a problem") 
    : m_message {message}
  {}
  virtual ~Trouble() = default;   // Base classes must have a virtual destructor!

  virtual std::string_view what() const { return m_message; }