Question

How can I derive a class from cout so that, for example, writing to it

new_cout << 'message';

would be equivalent to

cout << __FUNCTION__ << 'message' << 'end of message' << endl;

Answer 1

class Log { public:     Log(const std::string &funcName)     {         std::cout << funcName << ': ';     }      template <class T>     Log &operator<<(const T &v)     {         std::cout << v;         return *this;     }      ~Log()     {         std::cout << ' [end of message]' << std::endl;     } };  #define MAGIC_LOG Log(__FUNCTION__) 

Hence:

MAGIC_LOG << 'here's a message'; MAGIC_LOG << 'here's one with a number: ' << 5;