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.
I used to play this game on Wenquxing (An old PDA). Someday which I forget, I find this game is not available on computer. I did not searched an ideal one, and have to write it by myself.

The latest version is 1.1, released on Nov 24, 2011. Please Download it at Sourceforge.
4digits is released under GNU General Public License version 2.