Version 5.0 The LEDA User Manual

Equal is a class that compares two items of the template parameter T by means
of a method bool operator()(T,T);. There are some classes available for this
purpose: Equal, Unequal, LessThan, LessEqual, GreaterThan and
GreaterEqual with obvious semantics, where T is the type of the values. Predicates
of the STL can be used as well since they have the same interface.
13.11 Observer Node Iterator ( ObserverNodeIt )
1. Definition
An instance it of class ObserverNodeIt is an observer iterator. Any method
call of iterators will be “observed” by an internal object of class Obs.
Class ObserverEdgeIt and ObserverAdjIt are defined analogously, i.e. can be used for
edge iterators or adjacency iterators, respectively.
Precondition: The template parameter Iter must be a node iterator.
#include < LEDA/graph/graph iterator.h >
2. Creation
ObserverNodeIt it;
introduces a variable it of this class, not bound to an observer or
iterator.
ObserverNodeIt it(Obs& obs, const Iter& base it);
introduces a variable it of this class bound to the observer obs and
base it.
Precondition: Obs must have methods observe constructor(),
observe forward(), observe update(). These three methods
may have arbitrary return types (incl. void).
3. Operations
void
it.init(const Obs& obs, const Iter& base it)
initializes it, which is bound to obs and base it afterwards.
Precondition: it is not bound to an observer or iterator.
Obs& it.get observer( ) returns a reference to the observer to which it is
bound.