This document discusses infix, postfix, and prefix expressions and how to convert between them. It defines infix as having operators between operands, postfix as having operators after operands ordered by precedence, and prefix as having operators before operands ordered by precedence. It provides rules for operator precedence and explains how to convert an infix expression to both postfix and prefix notation with examples. Sample C code is also presented for converting an infix expression to postfix.

1. TOPIC : INFIX , POSTFIX , PREFIX EXPRESSIONS
PRESENTED BY :

2. CONTENTS.
 What are INFIX , POSTFIX , PREFIX EXPRESIONS
 Some rules for conversion
 Some Examples

3.  INFIX : an infix expression is one in which operators are located between their
operands.
Eg. (A + (B * C)) + D)
 POSTFIX : an postfix expression is one in which operators are located after its
operands, according to their precedence.
Eg. A B C * + D +
 PREFIX : an prefix expression is one in which operators are located before its operands,
according to their precedence.
Eg. + + A * B C D
What is INFIX , POSTFIX , PREFIX ?

4. SOME RULES FOR CONVERSION
 Highest priority -> ^
 Next priority -> / , *
 Least priority -> + , -
 No two operators of same priority can stay together in stack .
 Least priority operator cannot be placed above the highest priority operator
in stack.

5. INFIX TO POSTFIX
 Eg. (A + B / C * (D + E ) )
Input String Output Operator Stack
(A + B / C * (D + E ) ) (
(A + B / C * (D + E ) ) A (
(A + B / C * (D + E ) ) A (+
(A + B / C * (D + E ) ) A B (+
(A + B / C * (D + E ) ) A B (+/
(A + B / C * (D + E ) ) A B C (+/
(A + B / C * (D + E ) ) A B C / (+*
(A + B / C * (D + E ) ) A B C /
(+*(
(A + B / C * (D + E ) ) A B C / D (+*(+
(A + B / C * (D + E ) ) A B C / D E (+*(+
(A + B / C * (D + E ) ) A B C / D E + (+*
(A + B / C * (D + E ) ) A B C / D E + *+

6. INFIX TO PREFIX
 Eg . A + B * C – D + E
Input String Operator Stack Output
E E
+ + E
D + ED
- - ED+
C - ED+C
* - * ED+C
( - * ( ED+C
B+ - * ( ED+CB
A - * ( + ED+CBA
) - * ED+CBA+
- ED+CBA+*
ED+CBA+*-
OUTPUT -*+ABC+DE

7. C code for infix to postfix
 Lets see some examples