Core JavaScript 1.5 Guide:Operators:Arithmetic Operators

From MDC

[edit] Arithmetic Operators

Arithmetic operators take numerical values (either literals or variables) as their operands and return a single numerical value. The standard arithmetic operators are addition (+), subtraction (-), multiplication (*), and division (/). These operators work as they do in most other programming languages when used with floating point numbers (in particular, note that division by zero produces NaN). For example:

1 / 2      // returns 0.5 in JavaScript
1 / 2      // returns 0 in Java (neither number is explicitly a floating point number)

1.0 / 2.0  // returns 0.5 in both JavaScript and Java

In addition, JavaScript provides the arithmetic operators listed in the following table.

Operator	Description	Example
% (Modulus)	Binary operator. Returns the integer remainder of dividing the two operands.	12 % 5 returns 2.
++ (Increment)	Unary operator. Adds one to its operand. If used as a prefix operator (++x), returns the value of its operand after adding one; if used as a postfix operator (x++), returns the value of its operand before adding one.	If x is 3, then ++x sets x to 4 and returns 4, whereas x++ returns 3 and, only then, sets x to 4.
-- (Decrement)	Unary operator. Subtracts one from its operand. The return value is analogous to that for the increment operator.	If x is 3, then --x sets x to 2 and returns 2, whereas x-- returns 3 and, only then, sets x to 2.
- (Unary negation)	Unary operator. Returns the negation of its operand.	If x is 3, then -x returns -3.

Table 3.4: Arithmetic Operators