Search results
Results from the WOW.Com Content Network
A character literal is a type of literal in programming for the representation of a single character's value within the source code of a computer program. Languages that have a dedicated character data type generally include character literals; these include C , C++ , Java , [ 1 ] and Visual Basic . [ 2 ]
ASCII was incorporated into the Unicode (1991) character set as the first 128 symbols, so the 7-bit ASCII characters have the same numeric codes in both sets. This allows UTF-8 to be backward compatible with 7-bit ASCII, as a UTF-8 file containing only ASCII characters is identical to an ASCII file containing the same sequence of characters.
A code point is a value or position of a character in a coded character set. [9] A code space is the range of numerical values spanned by a coded character set. [9] [11] A code unit is the minimum bit combination that can represent a character in a character encoding (in computer science terms, it is the word size of the character encoding).
Furthermore, a "character" may require more than one code point (for instance with combining characters), depending on what is meant by the word "character". The fact that a character was historically stored in a single byte led to the two terms ("char" and "character") being used interchangeably in most documentation.
A one byte offset, such as the hexadecimal ASCII value of a character (e.g. X'29') can be used to point to an alternative integer value (or index) in an array (e.g., X'01'). In this way, characters can be very efficiently translated from 'raw data' to a usable sequential index and then to an absolute address without a lookup table.
The control characters in ASCII still in common use include: 0x00 (null, NUL, \0, ^@), originally intended to be an ignored character, but now used by many programming languages including C to mark the end of a string. 0x07 (bell, BEL, \a, ^G), which may cause the device to emit a warning such as a bell or beep sound or the screen flashing.
For example, PHP and Python allow this optional parameter, while Pascal and Java do not. With Common Lisp's string-trim function, the parameter (called character-bag) is required. The C++ Boost library defines space characters according to locale, as well as offering variants with a predicate parameter (a functor) to select which characters are ...
In computing, a code page is a character encoding and as such it is a specific association of a set of printable characters and control characters with unique numbers. Typically each number represents the binary value in a single byte. (In some contexts these terms are used more precisely; see Character encoding § Terminology.)