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0) Administrative
- hw: 10.1-2
- A4 questions?

A4 hints:

* The ONLY THINGS that may be static are main and console input stuff
* Main gets the filenames, makes sure they fit the requirements, then
  makes a POSCalculator object and tells it to process the files

* You MUST HAVE more than one or two instance methods to keep reasonable length
* You'll have some sort of "process" method with a loop that reads the lines
* Example: a separate method to process one line
* Continue by taking logical chunks out of that one to make others
* A method here will be a little longer than before, but should fit on a page

* What to do when you look at a line?   Ex: 3 + 4 - 1 =
a) Have you seen anything yet? If not, you expect a left operand.
   Store it and note that you've got one.
	- data members? double and boolean
b) If you've seen a left operand, have you seen an operator yet? If not,
   you expect one. Store it and note that you've got one.
	- data members? char and boolean
c) If you've seen an operator, you expect a right operand. Calculate and 
   store the result as a left operand. Unmark the operator.
	- data members? none
d) What if you see an equals? There must be something in the left operand,
   a value that's just been calculated, and you should print it to the file.
	- trickiness with handling end of file

* Remember to initialize all these data members in the constructor
* How do you tell whether the line has a double or an operator?
	- try to parse it. try block assumes it worked and handles operands,
	  catch block knows it didn't and handles operators

1) Last time- file I/O
- finish up stuff

2) Exam review

	A. Specific questions?

	B. Review answers

	C. Recent lab exercises

3) Pointers

- it's not tricky, but it's hard; mind the details
- work carefully, write out each step you take, and check your answers later
- play computer to work out loops and to check your written answers
- go over A2 and A3 so they're fresh in your mind
- do a string processing exercise from scratch for practice

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