用alpha-beta剪枝算法实现的一字棋（井字棋）对弈程序。由网上另外一个代码改进而来（感谢原作者）。增强了棋力-Alpha-beta pruning algorithm of the word chess-playing program (Tic-Tac-chess). Improvements comes from another online code (thanks to the original author). Enhance the playing strength