4digits is a guess-the-number puzzle game. It's called Bulls and Cows, and in China people simply call it Guess-the-Number. The game's objective is to guess a four-digit number in 8 times using as less time as possible. You do not need to install it to play. Just execute '4digits' or 'make' to generate the text version. Have fun! ----------------------------------- TODO * Internationalization. Please help me to improve this game, thank you!