Java question | Computer Science homework help

Java question | Computer Science homework help

[ad_1]

 Lab #1 — Building a CalculatorYour task for Lab #1 is to build a calculator in Java that has two modes, controllable by command-line options postfix and infix. In both modes the calculator will read lines of input from standard input. For each input line, the calculator will evaluate the expression that was input and print the result on a separate line. The program ends when it encounters the EOF character,similar to the behavior of most Unix utilities.To simplify matters regarding dealing with different types of numbers, in this assignment, all numbers are to be represented internally as either Java floatprimitives or Floatobjects depending on your implementation choices.Your calculator will implement the following operations:+, -, *, /^ (exponentiation: e.g., 2^3 = 8).Your calculator will implement expressions containing either a sole number or operations applied to numbers.Mode #1 — Postfix NotationThe first mode that you will implement is one where the calculator accepts anexpression that is expressed in postfix notation. For those of you familiar with HP’s line of scientific and graphing calculators, postfix notation is also known as RPN or Reverse Polish Notation, in honor of the Polish logician Jan Łukasiewicz who invented Polish notation, also known as prefix notation.Here are examples of expressions written in postfix notation with their conversions to infix notation and their evaluations:2 3 +2 + 352 3 + 5 *(2 + 3) * 5252 3 5 * +2 + (3 * 5)172 3 2 ^ * -10 –2 * (3 ^ 2) – -1028How an RPN calculator works internally is as follows: it maintains an internal stack that is used to store operands and intermediate results. Let’s use the expression “4 3 + 5 *” as an example. The first thing that we do is lexical analysis on the input string by first splitting the string by its whitespace characters and then performing the proper type conversions on the numbers, resulting in a list that looks like this:[4.0, 3.0, “+”, 5.0, “*”]Next, we iterate through the list. For each number, we push it onto the stack. Once we reach an operator on the list, we pop the stack twice, perform that operation on the popped numbers, and then push the result onto the stack. In this example, the elements 3.0 and 4.0 are popped from the stack. We then perform the “+” operation on the second and first elements popped from the stack (order matters for “-”, “/”, and “^”), and then push the result (12.0) onto the stack. Then, as we continue iterating through the list, we encounter 5.0, and thus we push it on the stack, resulting in a stack with the elements 12.0 (bottom) and 5.0 (top). Finally, the last token in the list is “*”, and so we pop the stack twice, multiplying 5.0 and 12.0 to get 60.0, and then we push it back on the stack.When we have exhausted the list of tokens, we pop the stack and print the popped value as the result of the expression.One of the nice properties of postfix notion is the lack of a need to specify operator precedence. It is this property that makes it possible to implement an RPN calculator without the need for specify a formal grammar for expressions. In fact, there are full-fledged programming languages such as Forth and PostScript that use postfix notation and rely on a stack.Mode #2 — Infix NotationUnlike a postfix calculator where parsing is a very straightforward task, parsing is not as straightforward in infix notation, since you have to concern yourself with expressions of arbitrary length and operator precedence. Your calculator will have to properly implement the PEMDAS (parentheses, exponents, multiplication, division, addition, subtraction) order of operations that are from elementary algebra.Thankfully with the help of parser generators such as ANTLR, you won’t have to deal with the labor of implementing parsing algorithms.Here is an excellent tutorial for using ANTLR:https://tomassetti.me/antlr-mega-tutorial/ (Links to an external site.). Please also refer to the main ANTLR website athttps://www.antlr.org (Links to an external site.).Your goals are the following:Write a BNF or EBNF grammar that is able to represent expressions in infix notation that is also able to implement the PEMDAS order of operations.Express that grammar as an ANTLR grammar.Use ANTLR to generate an abstract syntax tree.Traverse the abstract syntax tree to evaluate the expression. There are two ways of doing this: (1) either evaluating the abstract syntax tree directly, or (2) using the AST to generate a postfix notation representation of the expression, and then evaluating it as in Mode #1.Some Examples:$ java Calculator postfixCalculator> 2 4 * 2 ^ 10 –54Calculator> 55Calculator> 8 24 + 9 –23$ java Calculator infixCalculator> (2 * 4)^2 – 1054Calculator> 55Calculator> 8 + 24 – 923Deliverable:A collection of Java and ANTLR source code files in a *.zip archive, where the main method is located in a class called Calculator and in a file called Calculator.java.Grading Rubric:Mode #1 (Postfix Notation): 30%Mode #2 (Infix Notation Grammar and Parsing): 50%Mode #2 (Infix Notation Evaluation): 20%Note:Your code must compile in order for it to receive any credit; any submission that does not compile will receive a grade of 0%.   “Is this question part of your assignment? We Can Help!”

"96% of our customers have reported a 90% and above score. You might want to place an order with us."

Essay Writing Service
Affordable prices

You might be focused on looking for a cheap essay writing service instead of searching for the perfect combination of quality and affordable rates. You need to be aware that a cheap essay does not mean a good essay, as qualified authors estimate their knowledge realistically. At the same time, it is all about balance. We are proud to offer rates among the best on the market and believe every student must have access to effective writing assistance for a cost that he or she finds affordable.

Caring support 24/7

If you need a cheap paper writing service, note that we combine affordable rates with excellent customer support. Our experienced support managers professionally resolve issues that might appear during your collaboration with our service. Apply to them with questions about orders, rates, payments, and more. Contact our managers via our website or email.

Non-plagiarized papers

“Please, write my paper, making it 100% unique.” We understand how vital it is for students to be sure their paper is original and written from scratch. To us, the reputation of a reliable service that offers non-plagiarized texts is vital. We stop collaborating with authors who get caught in plagiarism to avoid confusion. Besides, our customers’ satisfaction rate says it all.

© 2022 Homeworkcrew.com provides writing and research services for limited use only. All the materials from our website should be used with proper references and in accordance with Terms & Conditions.

Scroll to Top