// Can you talk about infixes more?

unboxing & auto boxing

Token and instanceof

Iterator
	what does it do versus like just storing an int for iterations
	controlled by a loop? or is it for something else entirely?

try {
}
catch {
}

The different ways in which stacks can be implemented
In what situation a stack can be useful
Why accessors and mutators are used
How often accessors and mutators are used


Some of the infix/postfix stuff. I suppose it’s from being used to a general method of number input all my life.

// What is a tokenizer and what does it do?

postfix.push(pendingOps.pop()) ;

Things I did not understand:
       the while loop in doPostfixEval
       the small commented while loop in infix2postfix