（1）该类包含一个 3×3 的二维整型数组，其访问类型为 private （2）定义一个构造函数，用来将该数组初始化为 0 （3）允许 2 个玩家，当第 1 个玩家选定一个位置后，在该位置摆放一个 1； 当第 2 个玩家选定一个位置后，在该位置摆放一个 2； （4）在每一步后，判断游戏是否结束，是否出现赢家 -(1) This class contains a two-dimensional array of integers 33, whose access type is private (2) defines a constructor to initialize the array to 0 (3) allows two players, when the first one players　a location, place a 1 in that position　when the first two players selected a location, the location of a place 2　(4) after each step to determine whether the game is over, if there is a winner