Standard C++ LibraryCopyright 1996, Rogue Wave Software, Inc.

NAME

  Random_Access_Iterators  - An iterator that reads and writes, and provides
  random access to a container.

DESCRIPTION

  For a complete discussion of iterators, see the Iterators section of this
  reference.

  Iterators are a generalization of pointers that allow a C++ program to
  uniformly interact with different data structures.  Random access iterators
  can read and write, and provide random access to the containers they serve.
  These iterators satisfy the requirements listed below.

KEY TO ITERATOR REQUIREMENTS

  The following key pertains to the iterator requirements listed below:

  a and b   values of type X

  n   value of distance type

  u, Distance, tmp and m   identifiers

  r   value of type X&

  t   value of type T

REQUIREMENTS FOR RANDOM ACCESS ITERATORS

  The following expressions must be valid for random access iterators:

  X u   u might have a singular value

  X()   X() might be singular

  X(a)   copy constructor, a == X(a).

  X u(a)   copy constructor, u == a

  X u = a   assignment, u == a

  a == b, a != b   return value convertible to bool

  *a   return value convertible to T&

  a->m   equivalent to (*a).m

  ++r   returns X&

  r++   return value convertible to const X&

  *r++   returns T&

  --r   returns X&

  r--   return value convertible to const X&

  *r--   returns T&

  r += n   Semantics of --r or ++r n times depending on the sign of n

  a + n, n + a   returns type X

  r -= n   returns X&, behaves as r += -n

  a - n   returns type X

  b - a   returns Distance

  a[n]   *(a+n), return value convertible to T

  a < b   total ordering relation

  a > b   total ordering relation opposite to <

  a <= b   !(a < b)

  a >= b   !(a > b)

  Like forward iterators, random access iterators have the condition that  a
  == b implies *a == *b.

  There are no restrictions on the number of passes an algorithm may make
  through the structure.

  All relational operators return a value convertible to bool.

SEE ALSO

  Iterators, Forward Iterators, Bidirectional Iterators

STANDARDS CONFORMANCE

  ANSI X3J16/ISO WG21 Joint C++ Committee



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