Efficient string concatenation in C++

As with most things, it's easier not to do something than to do it.

If you want to output large strings to a GUI, it may be that whatever you're outputting to can handle the strings in pieces better than as a large string (for example, concatenating text in a text editor - usually they keep lines as separate structures).

If you want to output to a file, stream the data rather than creating a large string and outputting that.

I've never found a need to make concatenation faster necessary if I removed unnecessary concatenation from slow code.