Rectangle

代码说明：

  根据输入的长宽，计算Rectangle面积周长等功能，并画出在txt文件中(Rectangle Create a class Rectangle with attributes length and width, each of which defaults to 1 a. Provide member functions that calculate the perimeter and the area of the rectangle. b. Also provide set and get functions for the length and width attributes. The set functions should verify that length and width are each integer numbers larger than 0 and less than 20. c. Write draw function to display the Rectangle: in Assignment1. ) d. Write a driver program to test class Rectangle.)