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

What is called the basic operation of an algorithm, What is called the basi...

What is called the basic operation of an algorithm? The most significant operation of the algorithm is the operation contributing the most to the total running time is known as

Prefix and Postfix Expressions, Q.   Draw the expression tree of the infix ...

Q.   Draw the expression tree of the infix expression written below and then  convert it intoPrefix and Postfix expressions. ((a + b) + c * (d + e) + f )* (g + h )

What is an algorithm, What is an algorithm?  What are the characteristics o...

What is an algorithm?  What are the characteristics of a good algorithm? An algorithm is "a step-by-step process for accomplishing some task'' An algorithm can be given in many

Explain the halting problem, Explain the halting problem Given a comput...

Explain the halting problem Given a computer program and an input to it, verify whether the program will halt on that input or continue working indefinitely on it.

Circular queue, explain implementation of circular queue insert,delete oper...

explain implementation of circular queue insert,delete operations

All pairs shortest paths algorithm, In the last section, we discussed regar...

In the last section, we discussed regarding shortest path algorithm that starts with a single source and determines shortest path to all vertices in the graph. In this section, we

Comparisions and assignments in worst case, Q. Calculate that how many key ...

Q. Calculate that how many key comparisons and assignments an insertion sort makes in its worst case?        Ans: The worst case performance occurs in insertion

What is the best case complexity of quick sort, What is the best case compl...

What is the best case complexity of quick sort In the best case complexity, the pivot is in the middle.

Efficient way of storing two symmetric matrices, Explain an efficient way o...

Explain an efficient way of storing two symmetric matrices of the same order in memory. A n-square matrix array is said to be symmetric if a[j][k]=a[k][j] for all j and k. For

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 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