说明：  由实验图像可知，设计程序可以完成题目要求的，在确定步数n，生成一个在X-y平面格点上n步服从均匀分布的随机游走图。
(Designed by experiment image, the program can complete the topic request, the steps in determining n, generate a step on the x-y plane lattice n obey uniform distribution random walk.)