Send the last line of cout to a window

Question

In my application I have a console (which uses std::out) and a window (that has a function to show some text). What I'm looking for is a way to show the last line of cout in my window. I've read some articles about making a custom streambuf class or a struct that simply overloads the << operator. I can't overload the << operator because I'm not able to use things like endl if I do so.

Another post here suggest to define my own streambuf but I don't know if that's a good solution for my problem. Maybe someone can give me an advice on how I should implement this feature.

Answer 1

You can overload << for that purpose. To make it work with stream manipulators, you could use an internal std::stringstream:

class out
{
    std::ostringstream ss;
    std::string display_str;
  public:
    template <typename T> out &operator<<(T &&obj)
    {
        std::cout << obj;
        ss.str("");
        ss << obj;
        std::string tmp = ss.str();
        if (tmp.size() == 0)
            return *this;
        const char *ptr = &tmp[0], *start = ptr;
        while (*ptr)
        {
            if (*ptr == '\n')
                start = ptr+1;
            ptr++;
        }
        if (start != ptr)
            display_str = start;
        else
            display_str += start;
        update_display_string(display_str); // Replace this with your update function.
        return *this;
    }
};