1. Advanced Data Structure using C++

LECTURE NOTES OF ADVANCED DATA STRUCTURE (MT-CSE 110)
Infix to Prefix Conversion
The input for this conversion is infix expression E and output of this is equal to
expression P.This can be done by the use of stacks.
ALGORITHEM FOR CONVERSION:
1. Reverse the input string.
2.Examine the next element in the input .
3.If it is operand ,add it to the output string.
4.If it closing paranthesis,push it on stacks.
5.If it is an opertor ,then
(a) If stackes is empty ,push‐operation on stackes.
(b) If the top of stacks is closing paranthesis pus operation on stackes.
(c) If it has same or higer priority then the top of stackes ,pus operator on
stacks.
(d) Else pop the operator from the stacks and add it to output string ,repeate
S.
6. If it opening paranthesis,pop operator from stackes and add them to S until a
closing
Paranthesis is encounter .pop and discard the closing paranthsis .
7.If there is more input go to step 2.
8.If there is no more input ,unstacks the remaining operators and add them.
9.Reverse the output string .
Prepared By :­
Er. Harvinder Singh
Assist Prof., CSE, H.C.T.M (Kaithal) Page ‐ 175 ‐