Integer Literals

   

Integer literals are used to represent specific integer values. Because integers can be expressed as decimal (base 10), octal (base 8), or hexadecimal (base 16) numbers in Java, each representation has its own form of literal. In addition, integer literals can also be expressed with an uppercase L ( 'L' ) or lowercase L ( 'l' ) at the end to instruct the compiler to treat the number as a long (64-bit) integer.

As with C and C++, Java identifies any number that begins with a non-zero digit and does not contain a decimal point as a decimal integer literal (for example, any number between 1 and 9). To specify an octal literal, you must precede the number with a leading 0 (for example, 045 is the octal representation of 37 decimal). As with any octal representation, these literals can only contain the numerals 0 through 7. Hexadecimal integer literals are known by their distinctive 'zero-X' at the beginning of the token.

Note

Tokens are the identifiers, keywords, literals, separators, and operators of Java. In short, they are every element of your source code other than whitespace and comments, which are described later in this chapter. Of the token types, only the separators have not been introduced. As the name implies, these tokens serve the purpose of separating other elements of your code. The separators consist of

 (  )  {  }   [  ]  ;  ,  . 

Hex numbers are composed of the numerals 0 through 9 plus the Latin letters A through F (case is not important).

The following shows the largest and smallest values for integer literals in each of the three supported formats:

Largest 32-bit integer literal 2147483647
  017777777777
  0x7fffffff
Most negative 32-bit integer literal “2147483648
  020000000000
  0x80000000
Largest 64-bit integer literal 9223372036854775807L
  0777777777777777777777L
  0x7fffffffffffffffL
Most negative 64-bit integer literal “9223372036854775808L
  01000000000000000000000L
  0x8000000000000000L

Caution

Attempts to represent integers outside the range shown in this table using literals result in compile-time errors.


   


Special Edition Using Java 2 Standard Edition
Special Edition Using Java 2, Standard Edition (Special Edition Using...)
ISBN: 0789724685
EAN: 2147483647
Year: 1999
Pages: 353

flylib.com © 2008-2017.
If you may any questions please contact us: flylib@qtcs.net