I was trying to think of what devilish tricks they had come up with to read user input via printf, but alas they also use scanf. So the more accurate title wou

I was trying to think of what devilish tricks they had come up with to read user input via printf, but alas they also use scanf. So the more accurate title would be "Implementing Tic-Tac-Toe Using Only Printf and Scanf". Still, pretty neat! And should scare anyone using printf with user-supplied formatting strings, ie a great example of why that's a big no-no.