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

Implementing abstract data types, Implementing abstract data types A co...

Implementing abstract data types A course in data structures and algorithms is hence a course in implementing abstract data types. It may seem that we are paying a lot of atten

Write functions for both addition and subtraction, You will write functions...

You will write functions for both addition and subtraction of two numbers encoded in your data structure. These functions should not be hard to write. Remember how you add and subt

linear-expected-time algorithm, Implement a linear-expected-time algorithm...

Implement a linear-expected-time algorithm for selecting the k th smallest element Algorithm description 1. If |S| = 1, then k = 1 and return the element in S as the an

Write a procedure that produces independent stack, Write a procedure (make-...

Write a procedure (make-stack) that produces independent stack objects, using a message-passing style, e.g. (define stack1 (make-stack))  (define stack2 (make-stack)) W

Sparse matrix, memory address of any element of lower left triangular spars...

memory address of any element of lower left triangular sparse matrix

Definition of algorithm, Definition of Algorithm Algorithm must have th...

Definition of Algorithm Algorithm must have the following five characteristic features: 1.      Input 2.      Output 3.      Definiteness 4.      Effectiveness 5

Graph, explain the prims''s algorithm with suitable example?

explain the prims''s algorithm with suitable example?

Define wire-frame model, Define Wire-frame Model This skeletal view is ...

Define Wire-frame Model This skeletal view is called a Wire-frame Model. Although not a realistic representation  of the object, it is still very useful in the early stages of

Program insertion of a node into any circular linked list, Program Insertio...

Program Insertion of a node into any Circular Linked List Figure depicts a Circular linked list from which an element was deleted. ALGORITHM (Deletion of an element from a

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