CS 227   Lecture -*- Outline -*-

* Interactive Programming  (Chapter 6)

** batch
	So far, our programs have been "batch" programs
	   with I/O done by Scheme.
	That is, we type an expression, Scheme reads, 
	   evaluates, and then prints the result.

	But input is not under control of the program, and we 
	   do not get to print intermediate steps, or output
	   formatted the way we want.

** interactive
	Now, we will explore how to do that: interactive programming,
	   adapting what we learned about tracing.
	This will be programs like the "whos on first?" program.
	
** preview
	We look at I/O. I/O involves strings, and so we
	  review what we learned about strings first.
	I/O is a side effect, so we look at begin again (implicit begin 6.3).

	Then we write some programs that interact with the
	user, including a square root program, the Towers
	of Hanoi, and the Eight Queens problem.
	
	Along the way, we will investigate backtracking, a 
	technique useful in Artificial Intelligence.