Expression Tree, Programming Languages

Assignment Help:
For this assignment you will read a file expression.txt and create an expression tree. The expression will be a valid infix expression with the all the necessary parentheses so that there is no ambiguity in the order of the expression. You will evaluate the expression and print the result. You will also write the prefix and postfix versions of the same expression without any parentheses.

In an expression tree the nodes are either operators or operands. The operators will be in the set [''+'', ''-'', ''*'', ''/'']. The operands will be either integers or floating point numbers. All the operand nodes will be leaves of the expression tree. All the operator nodes will have exactly two children.

The outline of your program will be as follows:

class Stack (object):

class Node (object):

class Tree (object):
def __init__ (self):

def createTree (self, expr):

def evaluate (self, aNode):

def preOrder (self, aNode):

def postOrder (self, aNode):

def main():

main()
The function createTree() will take as input parameter an infix expression with parentheses as a String and create an Expression Tree from it. Assume that the expression string is valid.

You will take the expression string and break it into tokens. There are four different kinds of tokens - left parenthesis, right parenthesis, operator, and operand. When we read a left parenthesis we are starting a new expression and when we read a right parenthesis we are ending an expression. Here is the algorithm that you will use:

If the current token is a left parenthesis add a new node as the left child of the current node. Push current node on the stack and make current node equal to the left child.
If the current token is an operator set the current node''s data value to the operator. Push current node on the stack. Add a new node as the right child of the current node and make the current node equal to the right child.
If the current token is an operand, set the current node''s data value to the operand and make the current node equal to the parent by popping the stack.
If the current token is a right parenthesis make the current node equal to the parent node by popping the stack if it is not empty.
For the input file this is what your program will output:

( ( 8 + 3 ) * ( 7 - 2 ) ) = 55

Prefix Expression: * + 8 3 - 7 2

Postfix Expression: 8 3 + 7 2 - *

Related Discussions:- Expression Tree

Board coloring problem description, Board Coloring Problem Description ...

Board Coloring Problem Description In this problem you are given a board in which some of the elements are placed as shown in diagram below. Each element represents a color.

Write your own version of the strcmp function string_compare, Write your ow...

Write your own version of the strcmp function string_compare. Supply a main program that will test each of the 3 differing outcomes. int string_compare(char *s, cha

Django template, i''ve a problem with rendering a page with django template...

i''ve a problem with rendering a page with django templates

Javascript variables and datatypes, Let us first see the skeleton of a Java...

Let us first see the skeleton of a JavaScript file. JavaScript code should be written between the and tags. The value LANGUAGE = "JavaScript" indicates to the browser that J

What is cisc & risc?, Question 1 What is CISC & RISC? Explain their addres...

Question 1 What is CISC & RISC? Explain their addressing modes Question 2 Discuss the following- Design Specification of Assembler Design of Single Pass Assembler

determine if dna sequence is periodic or not, A string s is said to be per...

A string s is said to be periodic with a period α, if s is α k for some k > 2. (Note that α k is the string formed by concatenating k times.) A DNA sequence s is called a tande

Python (using os.walk), Using os.walk, write a script that will print the f...

Using os.walk, write a script that will print the filenames of zero length files. It should also print the count of zero length files.

Define a prolog predicate flatten, Define a Prolog predicate flatten(List, ...

Define a Prolog predicate flatten(List, FlattenedList) that asserts List is any nested list of atoms and FlattenedList is the same list with the nesting removed. The atom [] should

Define functions with no arguments and no return values, Define Functions w...

Define Functions with no arguments and no return values? When a function has no arguments it doesn't receive any data from the calling function. Likewise, it doesn't return any

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd