Package picasso.parser

Class ExpressionTreeGenerator

java.lang.Object

picasso.parser.ExpressionTreeGenerator

public class ExpressionTreeGenerator
extends Object

Parses a string into an expression tree based on rules for arithmetic.

Author:

former student solution, Robert C. Duvall (added comments, exceptions), Sara Sprenkle modified for Picasso

Field Summary

Fields

Modifier and Type	Field	Description
private static final int	ADD_OR_SUBTRACT
private static final int	CONSTANT
private static final int	GROUPING
private static final int	MULTIPLY_OR_DIVIDE

Constructor Summary

Constructors

Constructor	Description
ExpressionTreeGenerator()

Method Summary

Modifier and Type	Method	Description
Stack<Token>	infixToPostfix(String infix)	This method converts the String infix expression to a Stack of tokens, which are in postfix.
private Stack<Token>	infixToPostfix(List<Token> tokens)	This method converts the List of tokens (in infix order) to a Stack of tokens, which are in postfix.
ExpressionTreeNode	makeExpression(String infix)	Converts the given string into expression tree for easier manipulation.
private int	orderOfOperation(Token token)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

CONSTANT

private static final int CONSTANT

See Also:

• Constant Field Values

GROUPING

private static final int GROUPING

See Also:

• Constant Field Values

ADD_OR_SUBTRACT

private static final int ADD_OR_SUBTRACT

See Also:

• Constant Field Values

MULTIPLY_OR_DIVIDE

private static final int MULTIPLY_OR_DIVIDE

See Also:

• Constant Field Values

Constructor Details

ExpressionTreeGenerator

public ExpressionTreeGenerator()

Method Details

makeExpression

public ExpressionTreeNode makeExpression(String infix)

Converts the given string into expression tree for easier manipulation.

Parameters:

infix - - a non-empty expression to parse.

Returns:

ExpressionTreeNode representing the root node of the given infix formula

infixToPostfix

public Stack<Token> infixToPostfix(String infix)

This method converts the String infix expression to a Stack of tokens, which are in postfix.

Parameters:

infix - the String to parse, as we would typically write it

Returns:

a stack of tokens, in postfix order

infixToPostfix

private Stack<Token> infixToPostfix(List<Token> tokens)

This method converts the List of tokens (in infix order) to a Stack of tokens, which are in postfix.

Parameters:

tokens - the Tokens, in infix order

Returns:

a stack of tokens, in postfix order

orderOfOperation

private int orderOfOperation(Token token)

Parameters:

token -

Returns: