C++: How can i create a function that accepts concatenated strings as parameter?

Question

Can i design my logging-function in a way, that it accepts concatenated strings of the following form using C++?

int i = 1;
customLoggFunction(\"My Integer i         


        

Answer 1

One approach is a simple utility class that uses a standard stream in a templated member function:

class LogStream {
    public:
        template  LogStream& operator << (const T& rhs) {
            stream << rhs;
            return *this;
        }

    private:
        std::stringstream stream;
};

The stream member doing all the work is then used in the destructor,

~LogStream() {
    std::cout << stream.str() << std::endl;
}

and you can create temporary objects for passing your arguments to be concatenated:

LogStream() << "anything with std::ostream operator: " << 1.2345 << ' ' << std::hex << 12;

Additional state (e.g. a log level) can be passed to the constructor, often accompagnied by convenience functions like LogStream debug() { return LogStream(...); }. When you reach a certain point of sophistication though, you might want to switch to a logging library of course.