The document discusses the conversion of infix expressions to postfix expressions, explaining what a postfix expression is and providing various methods for the conversion. It includes an algorithm utilizing a stack to facilitate the conversion process, as well as examples to illustrate how to apply the algorithm step-by-step. Key concepts such as operands, operators, and precedence are also addressed to enhance understanding of the conversion methods.

1. Infix To Postfix Conversion

2. Contents:
• What is Postfix expression?
• Different methods to convert infix expression
to the postfix expression
• Algorithm to convert infix to postfix
expression using stack
• How to convert infix to postfix
using stack

3. What is a Postfix expression?
• An expression is a statement which contains operands and different
types of operator.
• For example, c=a+b is an expression in which a,b,c are operands
and +,= is an operator
• The above expression is nothing but an infix expression b’cause an
operator + comes in between operands a and b. Also, = comes in
between c and a
• Now, a postfix expression is that in which operators comes after
operands
• For example, infix expression a+b can be written as a postfix
expression ab+

4. Different methods to convert infix
expression to postfix expression:
• Manual method
• Fast method
• Conversion using Stack

5. Algorithm/Psuedocode:
S:stack
While(more token)
{
X <- next_token;
If(x is an operand)
print x
Else
{
While(precedence(x)<=precedence(top(s))
print(pop(s))
Push(s,x)
}
}
While(!empty(s))
print(pop(s));

6. HOW TO CONVERT INFIX EXPRESSION TO THE POSTFIX
EXPRESSION USING STACK ?
STACK INPUT EXPRESSION OUTPUT
( A+B^C )*D+E^5
EMPTY --------
( A+B^C)*D+E^5 ---------
( A
+B^C)*D+E^5

7. +
(
B^C)*D+E^5 AB
C)*D+E^5 AB
^
+
(
^
+
(
)*D+E^5 ABC

8. ^
+
(
)*D+E^5 ABC
Again
Empty
*D+E^5 ABC^+
*
+E^5
ABC^+
*
ABC^+D
D+E^5

9. +E^5
*
ABC^+D
As priority(*)>
priority(+),then * will be
popped from the stack
and printed as output
E^5
+
ABC^+D*
^5
+
ABC^+D*E

10. ^5
+
ABC^+D*E
5
+
ABC^+D*E
^
5
+
ABC^+D*E5
^

11. o expression ends
here
Empty
stack
ABC^+D*E5^+