Arithmetic Expression in Data Structure

An expression is defined as a combination of some operands and operators. Three types of notation for expression are available:

Infix Notation:

In this notation, operators are written in between the operands. The expression to multiply two numbers X and Y written in infix notation as :
X*Y

Prefix Notation:

In this notation operators are written before the operands. Prefix notation is also called polish notation. The polish mathematician Jan Lukasiewicz developed this notation. The expression to multiply two numbers X and Y are written in prefix notation as:
*XY

Postfix Notation:

In this notation, operators are written after the operands. This notation is also called the reverse polish notation. The expression to multiply two X and Y is written in prefix notation as:
XY*