data structure. infix 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