Version 5.0 The LEDA User Manual

ool it.valid( ) returns true if and only if end of sequence not yet
passed, i.e. if there is a face in the face set that was
not yet passed.
bool it.eol( ) returns !it.valid( ) which is true if and only if there is
no successor face left, i.e. if all faces of the face set
are passed (eol: end of list).
FaceIt& ++it performs one step forward in the list of faces of the
associated graph. If there is no successor face, it.eol( )
will be true afterwards. This method returns a reference
to it.
Precondition: it.valid( ) returns true.
FaceIt& −−it performs one step backward in the list of faces of
the associated graph. If there is no predecessor face,
it.eol( ) will be true afterwards. This method returns
a reference to it.
Precondition: it.valid( ) returns true.
4. Implementation
Creation of an iterator and all methods take constant time.
13.5 Adjacency Iterators for leaving edges ( OutAdjIt
)
1. Definition
a variable it of class OutAdjIt is an adjacency iterator that marks a node (which is fixed
in contrast to linear node iterators) and iterates over the edges that leave this node.
There is a variant of the adjacency iterators, so–called circulators which are heavily used
in the CGAL 2 . The names of the classes are OutAdjCirc and InAdjCirc and their
interfaces are completely equal to the iterator versions while they internally use e.g.
cyclic adj succ() instead of adj succ().
#include < LEDA/graph/graph iterator.h >
2. Creation
OutAdjIt it; introduces a variable it of this class associated with no graph.
2 See the CGAL homepage at http://www.cs.uu.nl/CGAL/.