Who can solve this C++ problem? (Making std::format work with your own object types)

Question

I want to be able to write the following:

std::format("My new box, Box({:.2},{:.2},{:.2})", box.getLength(), box.getWidth(), box.getHeight());

to

std::format("My new box, Box({:.2},{:.2},{:.2})", box.getLength(), box.getWidth(), box.getHeight());

This is what I've done so far:

template <>

class std::formatter<Box> :public std::formatter<double>

{

public:

    using std::formatter<double>::format;

    auto format(const Box& box, auto& context)

    {

        auto iter = format(box.getLength(), context);

        context.advance(iter);

        out = format(box.getWidth(), context);

        context.advance(iter);

        return format(box.getHeight(), context);

    

    }

}; The box class definition is inside another header file. As you can see this code above does not work.

Answer 1

First , which compiler does this compile on? I tried the online compiler here , latest gcc on local didnt work.

Second , If it compiled for you ,maybe you can shrae the error !1

Comments

Can you show me an example of how I can use std::format to print out 'Box' class object? The code I showed was my start but I'm not sure how to do this. I use Microsoft C++ compiler.

Answer 2

I don't know how fix that

Comments

Then don't comment as it is really not helping anyone. :)