why would std::string s("??<") output a { instead of ??< as expected???

Question

std::string s("??<");
std::cout << s << std::endl;

Why does that output { instead of ??<

I'm using Visual Studio 2008. I'm assume it's encoding it but why and what is the encoding called if that is what's happening?

This little %#$^*! caused me to look for a bug in my (unit test) code for 30 minutes before I figured out my string was mangled!! :(