Reverse Polish

Prefix - Infix - Postfix

Infix is standard maths notation, prefix is Polish Notation, and postfix is Reverse Polish Notation. You only need to know about Reverse Polish.

Reverse Polish Notation

Reverse Polish Notation is a mathematical notation, in which the operator follows the operands. The result is the removal of the need for parenthesis, because each operation only applies to a fixed number of values. You start from left to right and move to the first operator, this applies to the 2 previous terms.

You then move to the next operator to the right.

For example:

"3 4 +" is equal to 7, 3 + 4 using Infix notation.

"3 4 + 2 *" is equal to 14, (3+4)*2.

Because the operator applies to only two values (in this case) before it, there is no need for parenthesis.