Postfix expression algorithm, Data Structure & Algorithms

Assignment Help:

Write an algorithm to calculate a postfix expression.  Execute your algorithm using the given postfix expression as your input : a b + c d +*f ↑ .

To evaluate a postfix expression by using the given values:

clear the stack

symb  = next input character while(not end of input)

{

if (symb is an operand)

push onto the stack;

else

{

pop two operands from the stack;

result=op1 symb op2;

push result onto the stack;

}

symb = next input character;

}

return (pop (stack));

The input postfix expression is given as:- ab+cd+*f^

Symb                 Stack                                          Evaluation a    a

b                    a b

+                   pop a and b                                 (a + b) Push (a + b)

c                    (a + b) c

d                   (a + b) c d

+                   pop c and d                                 (c + d) Push (c + d)

*                    pop (a + b) and (c + d)                (a + b) * (c + d)

f                    (a + b) * (c + d) f

^                    pop (a + b) * (c + d) and f           (a + b) * (c + d) ^ f

The result of evaluation is ((a + b) * (c + d)) ^ f


Related Discussions:- Postfix expression algorithm

Determine about the post conditions assertion, Determine about the Post con...

Determine about the Post conditions assertion A  post condition is an assertion which should be true at completion of an operation. For instance, a post condition of the squ

Algorithm of binary search, Step 1: Declare array 'k' of size 'n' i.e. k(n)...

Step 1: Declare array 'k' of size 'n' i.e. k(n) is an array which stores all the keys of a file containing 'n' records Step 2: i←0 Step 3: low←0, high←n-1 Step 4: while (l

Determine in brief the painter algorithm, Determine in brief the Painter A...

Determine in brief the Painter Algorithm a) The farthest polygon, namely the rectangle PQRS, is stored first. (b) The next farthest, the quadrilateral ABCD, is superpo

Stack, infix to revrse polish

infix to revrse polish

Avl tree rotations, AVL trees and the nodes it contains must meet strict ba...

AVL trees and the nodes it contains must meet strict balance requirements to maintain O(log n) search time. These balance restrictions are kept maintained via various rotation func

Question, A binary search tree is used to locate the number 43. Which of th...

A binary search tree is used to locate the number 43. Which of the following probe sequences are possible and which are not? Explain. (a) 61 52 14 17 40 43 (b) 2 3 50 40 60 43 (c)

Algorithm for similar binary tree, Q. The two Binary Trees are said to be s...

Q. The two Binary Trees are said to be similar if they are both empty or if they are both non- empty and left and right sub trees are similar. Write down an algorithm to determine

Heights of 500 students `Algorithms`, Write an algorithm, using a flowchart...

Write an algorithm, using a flowchart, which inputs the heights of all 500 students and outputs the height of the tallest person and the shortest p erson in the school.

Algorithams example, any simple algoritham questions with answers

any simple algoritham questions with answers

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