need help to solve this problem

Question

1.00/5 (4 votes)

See more:

Expression Evaluation
Consider a pseudo code which takes following expression as input and produces given outputs.

Input Output

[ 0 ] 0
[ 1 ] 1
[ 0, 1 ] 1
[ 1, 1 ] 2
[ 1, [ 1, 2 ] ] -2
[ 1, 2, [ 8 ] ] -5
[ 1, [ 2 ], [ 3 ] ] -4
[ 9, [ 3, 4, [ [ 2 ] ] ] ] 0

Design a function/methos to implement above pseudo code by following prototype as

For CPP :

int ExpressEval(char * expression);

For C Sharp :

public int ExpressEval(string expression);

Input:

Accept expression to be evaluated as a string.

Output :

Return result of evaluation as an integer.

For e.g

consider input string to be "[1, 2 , [5 , 3 ] ]"

then your function must return -5.

Posted 2-Jun-11 22:23pm

invisible@123

Updated 2-Jun-11 22:41pm

Prerak Patel

v2

Add a Solution

Comments

walterhevedeich 3-Jun-11 4:26am

Seems like a homework. What kind of help do you need on this one?

Sergey Alexandrovich Kryukov 3-Jun-11 5:04am

What kind of help?
--SA

Rob Branaghan 3-Jun-11 5:08am

Looks a little bit like this

http://www.cis.upenn.edu/~matuszek/cit594-2002/Assignments/5-expressions.html

Sandeep Mewara 3-Jun-11 11:18am

What have you tried so far? Update the question with the effort.

1 solution

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

CPallini · Answer 1 · 2011-06-03T00:14:00

Solution 1

Well, skipping the most external '[]', you have the following grammar (if I'm right):

start: exp

exp: DIGIT | DIGIT ',' exp | '[' exp ']'    

NUM: '0' | '1' | .. | '9'

It looks simple enough in order to implement manually the parser.

Posted 3-Jun-11 0:14am

CPallini