需要求3个长方柱的体积，请编一个基于对象的程序。数据成员包括length（长）、

Width（宽）、height（高）。要求用成员函数实现以下功能：

(1) 由键盘分别输入3个长方柱的长、宽、高。

(2) 计算长方柱的体积。

(3) 输出3个长方柱的体积-To request the three rectangles of size, requested for an object-based programs. Data members include length (long), Width (W), height (H). Asked to use member functions to achieve the following functions: (1) input from the keyboard are three rectangular column length, width and height. (2) Calculate the volume of rectangular column. (3) Output 3 the size of rectangular column