用于 向窗口中两文本框内，分别输入一个点的x轴坐标，y轴坐标，用分支结构判断改点位于哪个象限，并显示在消息框中。-For the two text window fr a me, respectively, the input X shaft coordinate of a point to point, Y axis, which is located in the quadrant judgment with branch structure, and displayed in a message box.