matlab实现一个鱼箱的功能，可以添加鲨鱼和小鱼，小鱼随机移动，鲨鱼通过直线追上小鱼，追上以后吃掉（即小鱼消失）。-matlab the function of a fish tank, you can add the sharks and fish, the fish moves randomly, sharks through a straight line to catch up with the fish, catch up later, eat (ie, fish disappear