V
 
variable
(1) In programming languages, a language object that can take different values, one at a time. The values of a variable are usually restricted to a certain data type. I. See character variable. (2) In visual programming, a part that receives an identity at run time. A variable by itself contains no data or program logic; it must be connected in such a way that it receives run-time identity from a part elsewhere in the application. CB.
variant character
A character that is not a member of an invariant character set. See invariant character set.
VFT
Virtual function table.
VGA
See video graphics adapter.
video attributes
Characteristics of picture quality. The standard video attributes are brightness, contrast, freeze, hue, saturation, and sharpness.
video graphics adapter (VGA)
A graphics controller for color displays. It displays graphics with a resolution of 640 by 480 pixels in up to 256 colors. The pixel resolution of the video graphics adapter is 4:4. See super video graphics adapter.
videodisc
A disc on which programs have been recorded for playback on a computer or a television set; a recording on a videodisc. The most common format in the United States and Japan is an NTSC signal recorded on the optical reflective format.
virtual function
A function of a class that is declared with the keyword virtual. The implementation that is executed when a virtual function is called depends on the type of the object for which it is called. This is determined at run time.
virtual function table
In C++, an initialized table that facilitates polymorphism by indexing the addresses for the virtual functions available to a class hierarchy. The compiler creates at least one virtual function table for each class, unless the class has no virtual members. See polymorphism, virtual function.
visible identifiers
Identifiers defined in the current scope that are not hidden by other identifiers of the same name in an inner scope. An object is visible during its lifetime when the scopes in which it is defined are open. See lifetime of an object.
volatile
An attribute of a data object that indicates that the object is changeable beyond the control or detection of the compiler. Any expression referring to a volatile object, such as an assignment, is evaluated immediately.
 
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