（2） 发生一个值为0.0~10.0之间的随机数，并除以一个在前面板中输入的数。如果输入的数为0，则点亮LED，提示除数为0时，除法无效。-(2) a value of 0.0 to 5.0 occurred between random numbers and dividing by a number entered in the front panel. If the input is 0, then lit LED, prompted the divisor is 0, the divis