Interface Expressions

All Known Implementing Classes:

ExpressionTree

public interface Expressions

This interface was created as a framework for classes created to model expressions in prefix, postfix and infix form. I was given this class to use for my assignment and I generated the Javadocs for the class

Author:

Mrs. Teresa Kelly

Method Summary

Modifier and Type	Method	Description
TreeNode	buildTree(java.lang.String[] exp)	Builds a tree to represent the expression using a String[], where each item of the array is an element in an expression.
int	evalTree()	Evaluates the expression held in a tree in the class
int	postfixEval(java.lang.String[] exp)	Uses a stack to evaluate the expression given by exp, rather than building a tree and evaluating the tree.
java.lang.String	toInfixNotation()	Converts the current expression into infix notation with parentheses to help show the order of operations of infix notation
java.lang.String	toPostfixNotation()	Converts the current expression into postfix notation
java.lang.String	toPrefixNotation()	Converts the current expression into prefix notation

Method Detail

buildTree

TreeNode buildTree(java.lang.String[] exp)

Builds a tree to represent the expression using a String[], where each item of the array is an element in an expression.

Parameters:

exp - the expression broken up into an array

Returns:

a TreeNode that is the root of the tree that was built to represent the expression

evalTree

int evalTree()

Evaluates the expression held in a tree in the class

Returns:

the result of the expression sent into buildTree

toPrefixNotation

java.lang.String toPrefixNotation()

Converts the current expression into prefix notation

Returns:

a String representing the expression in prefix notation

toInfixNotation

java.lang.String toInfixNotation()

Converts the current expression into infix notation with parentheses to help show the order of operations of infix notation

Returns:

a String representing the expression in infix notation

toPostfixNotation

java.lang.String toPostfixNotation()

Converts the current expression into postfix notation

Returns:

a String representing the expression in postfix notation

postfixEval

int postfixEval(java.lang.String[] exp)

Uses a stack to evaluate the expression given by exp, rather than building a tree and evaluating the tree.

Parameters:

exp - the expression to be evaluated where each item of the String[] represents an item in the expression

Returns:

the result of the expression