// CS410 Summer 1998
// Homework 2
// Provided File

// An InfixTree is a data structure which represents an infix mathematical
// epxression as used by Calculator.  An expression can be:
//	* evaluated with eval
//  * expressed as a String with toString
//  * expressed as a String without redundant parentheses with toStringEC

// (Extend this class as hinted at in the project handout.)

abstract class InfixTree {
	abstract int eval() throws CalculatorDivideByZeroException;
	abstract public String toString();
	// un-comment if you do the extra credit:
	// abstract public String toStringEC(int prec);
}