CSC161 2010F, Class 09: Input and Output, Continued^2

Overview:
* Preliminary Reflections.
* Lab.

Admin:
* I expect that we'll finally get to the command line on Monday.
* Assignment 3 is now ready.
* It appears that some of you learned the disadvantages of waiting 
  until the last minute to do homework.  
  (Of course, the easy availability of solutions online helped.)

How do I get pi?  It's in a header file

        #include <math.h>
        circ = 2 * M_PI * rad;
        area = 2 * M_PI * M_PI * rad * rad * rad / circ;

Do we have to write about enums for HW3?  No

What if I want to let the user type "5 feet 11.2 inches"?  Then you should
do exercises 5 and 6.