Using stack to evaluate expression

 

Using a Stack to Evaluate an Expression

We often deal with arithmetic expressions written in what is called infix notation:

         Operand1 op Operand2

We have rules to indicate which operations take precedence over others, and we often use parentheses to override those rules.

Example: Suppose we have this infix expression Q:

         5 * ( 6 + 2 ) – 12 / 4

We can use two stacks to evaluate the expression: a stack for operands, a stack for operators (and parenthesis). We can split the string into array of tokens.

  1. While there are still tokens to be read in,

   1.1 Get the next token.

   1.2 If the token is:

       1.2.1 A number: push it onto the value stack.

       1.2.2 A variable: get its value, and push onto the value stack.

       1.2.3 A left parenthesis: push it onto the operator stack.You can also
choose to push the left parenthesis into the operand stack.

       1.2.4 A right parenthesis:

         1 While the thing on top of the operator stack is not a

           left parenthesis,

             1 Pop the operator from the operator stack.

             2 Pop the value stack twice, getting two operands.

             3 Apply the operator to the operands, in the correct order.

             4 Push the result onto the value stack.

         2 Pop the left parenthesis from the operator stack, and discard it.

       1.2.5 An operator (call it thisOp):

         1 While the operator stack is not empty, and the top thing on the

           operator stack has the same or greater precedence as thisOp,

           1 Pop the operator from the operator stack.

           2 Pop the value stack twice, getting two operands.

           3 Apply the operator to the operands, in the correct order.

           4 Push the result onto the value stack.

         2 Push thisOp onto the operator stack.

  1. While the operator stack is not empty,

    1 Pop the operator from the operator stack.

    2 Pop the value stack twice, getting two operands.

    3 Apply the operator to the operands, in the correct order.

    4 Push the result onto the value stack.

  1. At this point the operator stack should be empty, and the value

   stack should have only one value in it, which is the final result.

Note: Pay attention to negative operator and parenthesis.

Requirements:

1. Submit the repl.it link of the program

2. Copying code from others or from the Internet is considered as cheating and will result in 0 for the project

Calculate the price of your order

550 words
We'll send you the first draft for approval by September 11, 2018 at 10:52 AM
Total price:
$26
The price is based on these factors:
Academic level
Number of pages
Urgency
Basic features
  • Free title page and bibliography
  • Unlimited revisions
  • Plagiarism-free guarantee
  • Money-back guarantee
  • 24/7 support
On-demand options
  • Writer’s samples
  • Part-by-part delivery
  • Overnight delivery
  • Copies of used sources
  • Expert Proofreading
Paper format
  • 275 words per page
  • 12 pt Arial/Times New Roman
  • Double line spacing
  • Any citation style (APA, MLA, Chicago/Turabian, Harvard)

Our guarantees

Delivering a high-quality product at a reasonable price is not enough anymore.
That’s why we have developed 5 beneficial guarantees that will make your experience with our service enjoyable, easy, and safe.

Money-back guarantee

You have to be 100% sure of the quality of your product to give a money-back guarantee. This describes us perfectly. Make sure that this guarantee is totally transparent.

Read more

Zero-plagiarism guarantee

Each paper is composed from scratch, according to your instructions. It is then checked by our plagiarism-detection software. There is no gap where plagiarism could squeeze in.

Read more

Free-revision policy

Thanks to our free revisions, there is no way for you to be unsatisfied. We will work on your paper until you are completely happy with the result.

Read more

Privacy policy

Your email is safe, as we store it according to international data protection rules. Your bank details are secure, as we use only reliable payment systems.

Read more

Fair-cooperation guarantee

By sending us your money, you buy the service we provide. Check out our terms and conditions if you prefer business talks to be laid out in official language.

Read more