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

Differences between user and kernel level threads, Question : (a) Many ...

Question : (a) Many systems provide support for both user threads and kernel threads, resulting in different multithreading models. What are the two differences between user

Simple encryption, i have to make a program that encrypt a text to numbers,...

i have to make a program that encrypt a text to numbers, i don''t know what is wrong in my code, the example of what i need: text: hi >> number: 17 23

Little Man Computer, 1) Write a program that takes an input value (for exam...

1) Write a program that takes an input value (for example, a number 5). The output should be sum of all numbers from 1 to the value input by the user (in this example, the output w

Identify the type of addressing, specify the function of the instruction an...

specify the function of the instruction and also specify whether its right or wrong-: (5) 1) MOV [BX],AX? Register Indirect addressing 2) MOV CX,[BX+DI]?Base plus index add

Wap for intelligent agent able to play block dominoes game, Objective: ...

Objective: In a programming language of your choice, write an intelligent agent able to play block Dominoes against a player. Together with this assignment you will find two pa

Ado. net, ADO. NET ADO.NET (ActiveX Information Things for .NET) is a set o...

ADO. NET ADO.NET (ActiveX Information Things for .NET) is a set of programs elements that developers can use to accessibility data and data solutions. It is an element of the platf

Get variable data, How do i get back data from a FOR loop in order to prin...

How do i get back data from a FOR loop in order to print them on screen?

Depth estimation from a single view camera, i doing a project about depth e...

i doing a project about depth estimation, i have done some research, and i used the block matching algorithm to get the motion vectors from the image sequences, i now have the prob

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