CSC220 Programming Project 2 Specification Taken from Project 7, Chapter 5, Page 178 I have modified specification and requirements of this project Ref http www gigamonkeys com book (see chap 10) In the language Lisp, each of the four basic arithmetic operators appears before an arbitrary number of operands, which are separated by spaces The resulting expression is enclosed in parentheses The operators behave as follows ( a b c ) returns the sum of all the operands, and ( ) returns 0 ( a b c ) returns a b c , and ( a) returns a ( a b c ) returns the product of all the operands, and ( ) returns 1 ( a b c ) returns a b c , and ( a) returns 1 a Note may have zero operand must have at least one operand You can form larger arithmetic expressions by combining these basic expressions using a fully parenthesized prefix notation For example, the following is a valid Lisp expression ( ( 6) ( 2 3 4) ( ( 3) ( 1) ( 2 3 1)) ( )) This expression is evaluated successively as follows ( ( 6) ( 2 3 4) ( 3 1 2) ( )) ( 6 24 1 5 0 0) 16 5 Requirements Design and implement an algorithm that uses Java API stacks to evaluate a Valid Lisp expression composed of the four basic operators and integer values Valid tokens in an expression are '(',')',' ',' ',' ',' ',and positive integers ( 0) Display result as floting point number with at 2 decimal places Negative number is not a valid input operand, e g ( 2 3) However, you may create a negative number using parentheses, e g ( ( 2)3) There may be any number of blank spaces, 0, in between tokens Thus, the following expressions are valid ( ( 6)3) ( ( 20 30)) Must use Java API Stack class in this project Ref http docs oracle com javase 7 docs api java util Stack html Must throw LispExprEvaluatorException to indicate errors Must not add new or modify existing data fields Must implement these methods public LispExprEvaluator() public LispExprEvaluator(String currentExpression) public void reset(String currentExpression) public double evaluate() private void evaluateCurrentOperation() You may add new private methods package PJ2 import java util public class LispExprEvaluator Current input Lisp expression private String currentExpr Main expression stack current operation stack, see algorithm in evaluate() private Stack exprStack private Stack computeStack default constructor set currentExpr to create stack objects public LispExprEvaluator() add statements constructor with an input expression set currentExpr to currentExpression create stack objects public LispExprEvaluator(String currentExpression) add statements set currentExpr to currentExpression clear stack objects public void reset(String currentExpression) add statements This function evaluates current operator with its operands See complete algorithm in evaluate() Main Steps Pop operands from exprStack and push them onto computeStack until you find an operator Apply the operator to the operands on computeStack Push the result into exprStack private void evaluateCurrentOperation() add statements This funtion evaluates current Lisp expression in currentExpr It return result of the expression The algorithm Step 1 Scan the tokens in the string Step 2 If you see an operand, push operand object onto the exprStack Step 3 If you see ( , next token should be an operator Step 4 If you see an operator, push operator object onto the exprStack Step 5 If you see ) steps in evaluateCurrentOperation() Step 6 Pop operands and push them onto computeStack until you find an operator Step 7 Apply the operator to the operands on computeStack Step 8 Push the result into exprStack Step 9 If you run out of tokens, the value on the top of exprStack is is the result of the expression public double evaluate() only outline is given you need to add statements local variables you may delete or modify any statements in this method use scanner to tokenize currentExpr Scanner currentExprScanner new Scanner(currentExpr) Use zero or more white space as delimiter, which breaks the string into single character tokens currentExprScanner currentExprScanner useDelimiter( s ) Step 1 Scan the tokens in the string while (currentExprScanner hasNext()) Step 2 If you see an operand, push operand object onto the exprStack if (currentExprScanner hasNextInt()) This force scanner to grab all of the digits Otherwise, it will just get one char String dataString currentExprScanner findInLine( d ) more else Get next token, only one char in string token String aToken currentExprScanner next() char item aToken charAt(0) switch (item) Step 3 If you see ( , next token shoube an operator Step 4 If you see an operator, push operator object onto the exprStack Step 5 If you see ) steps in evaluateCurrentOperation() default error throw new LispExprEvaluatorException(item is not a legal expression operator ) end switch end else end while Step 9 If you run out of tokens, the value on the top of exprStack is is the result of the expression return result return 0 0 change this statement DO NOT MODIFY ANY STATEMENTS BELOW This static method is used by main() only private static void evaluateExprTest(String s, LispExprEvaluator expr, String expect) Double result System out println( Expression s) System out printf( Expected result s , expect) expr reset(s) try result expr evaluate() System out printf( Evaluated result 2f , result) catch (LispExprEvaluatorException e) System out println( Evaluated result e) System out println( ) define few test cases, exception may happen public static void main (String args ) LispExprEvaluator expr new LispExprEvaluator() String test1 ( ( 6) ( 2 3 4) ( ( 3) ( 1) ( 2 3 1)) ( )) String test2 ( ( 632) ( 21 3 4) ( ( 32) ( 1) ( 21 3 1)) ( )) String test3 ( ( 2) ( 2) ( ( 1) ( 1) ( 2 1 ))( )) String test4 ( ( 2)( )) String test5 ( ( 2 3 0)) String test6 ( ( 2) ( 2) ( ( 1) ( 3) ( 2 1 )))) String test7 ( ( ) ) String test8 ( ( 6) ( 2 3 4) ( ( 3) ( 1) ( )) ( 1)) evaluateExprTest(test1, expr, 16 50 ) evaluateExprTest(test2, expr, 378 12 ) evaluateExprTest(test3, expr, 4 50 ) evaluateExprTest(test4, expr, 0 50 ) evaluateExprTest(test5, expr, Infinity or LispExprEvaluatorException ) evaluateExprTest(test6, expr, LispExprEvaluatorException ) evaluateExprTest(test7, expr, LispExprEvaluatorException ) evaluateExprTest(test8, expr, LispExprEvaluatorException ) I have also attached the exception class and test class in case needed for aid The only modifiable file is the one above these are just to test Do not modify this file LispExprEvaluatorException class It is used by LispExpressionEvaluator package PJ2 public class LispExprEvaluatorException extends RuntimeException public LispExprEvaluatorException() this( ) public LispExprEvaluatorException(String errorMsg) super(errorMsg) import PJ2 import java util Do not modify this file Simple test program which allows user to input Lisp expr string To terminate type exit public class PJ2 Test public static void main (String args ) create a LispExprEvaluator object LispExprEvaluator expr new LispExprEvaluator() scan input expr string Scanner scanner current expr string and its result String inputExpr double result int i 0 scanner new Scanner( System in ) scanner for input do try System out print( input an expression string ) scan next input line inputExpr scanner nextLine() if (inputExpr equals( exit )) break loop i System out println( Evaluate expression i inputExpr) expr reset(inputExpr) result expr evaluate() System out printf( Result 2f , result) end try catch ( LispExprEvaluatorException e ) System err printf( Exception s , e) end catch exception here, continue to next loop while ( true ) end do while end main

The Answer is in the image, click to view ...

Answered step by step

Verified Expert Solution

Link Copied!

Question

1 Approved Answer

Posted on Sep 22, 2024

************************************************************************************ * * CSC220 Programming Project#2 * * * * Specification: * * Taken from Project 7, Chapter 5, Page 178 * I have modified

************************************************************************************  *  * CSC220 Programming Project#2  *  *  *  * Specification:  *  * Taken from Project 7, Chapter 5, Page 178  * I have modified specification and requirements of this project  *  * Ref: http://www.gigamonkeys.com/book/ (see chap. 10)  *  * In the language Lisp, each of the four basic arithmetic operators appears  * before an arbitrary number of operands, which are separated by spaces.  * The resulting expression is enclosed in parentheses. The operators behave  * as follows:  *  * (+ a b c ...) returns the sum of all the operands, and (+) returns 0.  *  * (- a b c ...) returns a - b - c - ..., and (- a) returns -a.  *  * (* a b c ...) returns the product of all the operands, and (*) returns 1.  *  * (/ a b c ...) returns a / b / c / ..., and (/ a) returns 1/a.  *  * Note: + * may have zero operand  * - / must have at least one operand  *  * You can form larger arithmetic expressions by combining these basic  * expressions using a fully parenthesized prefix notation.  * For example, the following is a valid Lisp expression:  *  * (+ (- 6) (* 2 3 4) (/ (+ 3) (* 1) (- 2 3 1)) (+))  *  * This expression is evaluated successively as follows:  *  * (+ (- 6) (* 2 3 4) (/ 3 1 -2) (+))  * (+ -6 24 -1.5 0.0)  * 16.5  *  * Requirements:  *  * - Design and implement an algorithm that uses Java API stacks to evaluate a  * Valid Lisp expression composed of the four basic operators and integer values.  * - Valid tokens in an expression are '(',')','+','-','*','/',and positive integers (>=0)  * - Display result as floting point number with at 2 decimal places  * - Negative number is not a valid "input" operand, e.g. (+ -2 3)  * However, you may create a negative number using parentheses, e.g. (+ (-2)3)  * - There may be any number of blank spaces, >= 0, in between tokens  * Thus, the following expressions are valid:  * (+ (-6)3)  * (/(+20 30))  *  * - Must use Java API Stack class in this project.  * Ref: http://docs.oracle.com/javase/7/docs/api/java/util/Stack.html  * - Must throw LispExprEvaluatorException to indicate errors  * - Must not add new or modify existing data fields  * - Must implement these methods :  *  * public LispExprEvaluator()  * public LispExprEvaluator(String currentExpression)  * public void reset(String currentExpression)  * public double evaluate()  * private void evaluateCurrentOperation()  *  * - You may add new private methods  *  *************************************************************************************/  package PJ2; import java.util.*; public class LispExprEvaluator { // Current input Lisp expression private String currentExpr; // Main expression stack & current operation stack, see algorithm in evaluate() private Stack

Question

************************************************************************************ * * CSC220 Programming Project#2 * * * * Specification: * * Taken from Project 7, Chapter 5, Page 178 * I have modified

Step by Step Solution

Step: 1

Get Instant Access to Expert-Tailored Solutions

Step: 2

Step: 3

Ace Your Homework with AI

Recommended Textbook for

Database Theory And Application Bio Science And Bio Technology International Conferences Dta And Bsbt 2010 Held As Part Of The Future Generation Information Technology Conference Fgit 2010 Jeju Island Korea December 2010 Proceedings

Students also viewed these Databases questions

Question

Question

Question

Question

Question

Question

Question

Question

Question

Question

Question

Question

Question

Question