floatingpoint number
A real number (that is, a number that can contain a fractional part). The following are floatingpoint numbers:
3.0
111.5
½
3E5
The last example is a computer shorthand for scientific notation. It means 3*105 (or 10 to the negative 5th power multiplied by 3).
In essence, computers are integer machines and are capable of representing real numbers only by using complex codes. The most popular code for representing real numbers is called the IEEE FloatingPoint Standard .
The term floating point is derived from the fact that there is no fixed number of digits before and after the decimal point; that is, the decimal point can float. There are also representations in which the number of digits before and after the decimal point is set, called fixedpointrepresentations. In general, floatingpoint representations are slower and less accurate than fixedpoint representations, but they can handle a larger range of numbers.
Note that most floatingpoint numbers a computer can represent are just approximations. One of the challenges in programming with floatingpoint values is ensuring that the approximations lead to reasonable results. If the programmeris not careful, small discrepancies in the approximations can snowball to the point where the final results become meaningless.
Because mathematics with floatingpoint numbers requires a great deal of computing power, many microprocessors come with a chip, called a floating point unit (FPU ), specialized for performing floatingpoint arithmetic. FPUs are also called math coprocessors and numeric coprocessors.
WEBOPEDIA WEEKLY
Stay up to date on the latest developments in Internet terminology with a free weekly newsletter from Webopedia. Join to subscribe now.
We Recommend

Datamation Hangouts with Tech Experts
Watch Datamation's editor James Maguire moderate roundtable discussions with tech experts from companies such as Accenture, Dell, Blue Jeans Network, Microsoft and more »