Algorithm to evaluate expression given in postfix notation , Data Structure & Algorithms

Assignment Help:

Q. Write down an algorithm to evaluate an expression given to you in postfix notation. Show the execution of your algorithm for the following given expression.

AB^CD-EF/GH+/+*                                                                               

Ans.

Algorithm to evaluate Post fix Expression is shown as follows

 

Opndstk = the empty stack;

/*scan the input string reading one */

/*element at a time into symb */

while ( not end of input){

symb  = next input character;

if (symb is an operand)

push (opndstk, symb);

else

{

/* symb is an operator */

opnd 2 = Pop (opnd stk);

opnd 1 = Pop (opnd stk);

value = result of applying symb to opnd 1 and opnd 2;

push (opndstk,value);

}/*end else */

}/*end while */

return (pop (opnd stk));

AB^CD-EF/GH+/+*

Symb

Opnd1

Opnd2

Value

Opndstk

A

 

 

 

A

B

 

 

 

A,B

^

A

B

A^B

A^B

C

A

B

A^B

A^B,C

D

A

B

A^B

A^B,C,D

-

C

D

C-D

A^B,C-D

E

C

D

C-D

A^B,C-D,E

F

C

D

C-D

A^B,C-D,E,F

/

E

F

E/F

A^B,C-D,E/F

G

E

F

E/F

A^B,C-D,E/F,G

H

E

F

E/F

A^B,C-D,E/F,G,H

+

G

H

G+H

A^B,C-D,E/F,G+H

/

E/F

G+H

(E/F)/(G+H)

A^B,C-D, (E/F) /(G+H)

+

C-D

(E/F)/(G+H)

(C-D)+(E/F)/(G+H)

A^B,(C-D)+

(E/F)/(G+H)

*

A^B

(C-

D)+(E/F)/(G+H)

A^B*((C-D)+

(E/F)/(G+H))

A^B*((C-D)+

(E/F)/(G+H))


Related Discussions:- Algorithm to evaluate expression given in postfix notation

Conversion of general trees to binary trees, Taking a suitable example expl...

Taking a suitable example explains how a general tree can be shown as a Binary Tree. Conversion of general trees to binary trees: A general tree can be changed into an equiv

Usage of linked lists for polynomial manipulation, Q. Establish the usage o...

Q. Establish the usage of linked lists for polynomial manipulation.                                       Ans. Usag e of Linked List for Polynomial Manipulation. Link

Deletion algorithm for dequeue, Deletion Algorithm for dequeue Step 1:...

Deletion Algorithm for dequeue Step 1: [check for underflow]   If front = 0 and rear = 0   Output "underflow" and return Step 2: [delete element at front end]   If front

Algorithm to insert element to a max-heap sequentially, Q. Write  down the ...

Q. Write  down the  algorithm  to  insert  an  element  to  a  max-heap  which  is  represented sequentially.           Ans: The algorithm to insert an element "newkey" to

Explain open addressing, Open addressing The easiest way to resolve a c...

Open addressing The easiest way to resolve a collision is to start with the hash address and do a sequential search by the table for an empty location.

What is solid modeling, What is Solid modeling Solid modeling is the mo...

What is Solid modeling Solid modeling is the most powerful of the 3-D modeling technique. It provides the user with complete information about the model. Defining an object wit

Binary search, Explain binary search with an example

Explain binary search with an example

Program, insertion and deletion in a tree

insertion and deletion in a tree

Avl tree, Example: (Single rotation into AVL tree, while a new node is inse...

Example: (Single rotation into AVL tree, while a new node is inserted into the AVL tree (LL Rotation)) Figure: LL Rotation The rectangles marked A, B & C are trees

Simplifying assumptions of wire frame representation, Simplifying Assumptio...

Simplifying Assumptions of wire frame representation Neglect colour - consider Intensity: For now we shall forget about colour and restrict our discussion just to the intensi

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