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

Pascal program, Pascal program: Exactly what you need to do to generat...

Pascal program: Exactly what you need to do to generate your empirical data is specific to your individual assignment. However, some rules apply to all of you: 1. The gener

What are the characteristics of a good algorithm, What is an algorithm? Wha...

What is an algorithm? What are the characteristics of a good algorithm? An algorithm is defined as “a step-by-step procedure of accomplishing some task'''' An algorithm may be sh

Program for keep track of the titles of ebooks, This assignment will just f...

This assignment will just focus on NookyKindle eBook orders.  That is, we'll be keeping track of the titles of eBooks and the number of orders for that particular eBook during a pa

Use an insertion sort to sort an array, Use an insertion sort to sort an ar...

Use an insertion sort to sort an array (sequence) of long word integers. The size of the list will appear just before the list itself. Use the same labels as in this example: LE

What is an authentication subsystem, Question: (i) All Security authen...

Question: (i) All Security authentication mechanism that run on the TRU64 Unix Operating system run under the Security Integration Architecture (SIA ) layer. Explain with di

Class registration, using UML 1- Identify primary classes 2- Scenario d...

using UML 1- Identify primary classes 2- Scenario description 3- Class diagrams 4- Sequence diagrams

Python , Write a script that will list and count all of the images in a giv...

Write a script that will list and count all of the images in a given HTML web page. Each image starts with

Determine the effect of class isze on test scores, Of the 6,325 kindergarte...

Of the 6,325 kindergarten students who participated in the study, almost half or 3,052 were eligible for a free lunch program. The categorical variable sesk (1 == free lunch, 2 = n

Cobol, Need help with a cobol program.

Need help with a cobol program.

Type of linear programming - dea, Type of Linear Programming - DEA The ...

Type of Linear Programming - DEA The Express Dry Cleaners currently has four locations in the Chicago area and willing be opening the fifth in the very near future.  Mr. James,

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