Write the definition of the member function set so that the instance variables are set according to the parameters. Write the definition of the member function manipulate that returns a decimal number as follows: If the value of description is "rectangle", it returns first * second; if the value of description is "circle", it returns the area of the circle with radius first; if the value of description is "sphere", it returns the volume of the sphere with radius first; if the value of description is "cylinder", it returns the volume of the cylinder with radius first and height second; otherwise, it returns the value -1. g