Infix notation

Infix notation is the common arithmetic and logical formula notation, in which operators are written infix-style between the operands they act on (e.g. 2 + 2). Infix notation is more difficult to parse by computers than prefix notation ( e.g. + 2 2 ) or postfix notation ( e.g. 2 2 + ). However many programming languages use it due to its familiarity. It is more used in arithmetic, e.g. 2+2, 5×6.

In infix notation, unlike in prefix or postfix notations, parentheses surrounding groups of operands and operators are necessary to indicate the intended order in which operations are to be performed. In the absence of parentheses, certain precedence rules determine the order of operations.

Infix notation may also be distinguished from function notation, where the name of a function suggests a particular operation, and its arguments are the operands. An example of such a function notation would be S(1,3) in which the function S denotes addition: S(1,3) = 1+3 = 4.

See also

• Tree traversal: Infix (In-order) is also a tree traversal order. It is described in a more detailed manner on this page.
• Calculator input methods: comparison of notations as used by pocket calculators
• postfix notation, also called Reverse Polish notation
• prefix notation, also called Polish notation
• Shunting yard algorithm, used to convert infix notation to postfix notation or to a tree
• Operator (programming)

External links

• RPN or DAL? A brief analysis of Reverse Polish Notation against Direct Algebraic Logic
• Infix to postfix convertor