设计一个常用圆形体体积计算器，采用命令方式输入1、2、3，分别选择计算球体、圆柱体、圆锥体的体积，并输入计算所需相应参数。 -Design a common circular body volume calculator, use the command mode input 1,2,3, were selected calculation sphere, cylinder, cone size, and enter the appropriate parameters to calcula