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

Complexity, Complexity : How do the resource needs of a program or algorith...

Complexity : How do the resource needs of a program or algorithm scale (the growth of resource requirements as a function of input). In other words, what happens with the performan

Implementation of stack, In this unit, we have learned how the stacks are i...

In this unit, we have learned how the stacks are implemented using arrays and using liked list. Also, the advantages and disadvantages of using these two schemes were discussed. Fo

Conversion of general trees into the binary trees, By taking an appropriate...

By taking an appropriate example explain how a general tree can be represented as a Binary Tree.                                                                    C onversio

Illumination of wire frame, Illumination of wire frame The colour or sh...

Illumination of wire frame The colour or shade that a surface appears to the human eye depends primarily on three  factors : Colour and strength of incoming illumination

Algorithm for stack using array, write an algorithm for stack using array p...

write an algorithm for stack using array performing the operations as insertion ,deletion , display,isempty,isfull.

Types of tree ?, Binary: Each node has one, zero, or two children. This ...

Binary: Each node has one, zero, or two children. This assertion creates many tree operations efficient and simple. Binary Search : A binary tree where each and every left

Branch and Bound method, give some examples of least cost branch and bound ...

give some examples of least cost branch and bound method..

Explain memory allocation strategies, Memory Allocation Strategies If i...

Memory Allocation Strategies If it is not desirable to move blocks of due storage from one area of memory to another, it must be possible to relocate memory blocks that have be

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