deba@937: /* -*- C++ -*-
deba@937:  * src/lemon/skeletons/graph.h - Part of LEMON, a generic C++ optimization library
deba@937:  *
deba@937:  * Copyright (C) 2004 Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
deba@937:  * (Egervary Combinatorial Optimization Research Group, EGRES).
deba@937:  *
deba@937:  * Permission to use, modify and distribute this software is granted
deba@937:  * provided that this copyright notice appears in all copies. For
deba@937:  * precise terms see the accompanying LICENSE file.
deba@937:  *
deba@937:  * This software is provided "AS IS" with no warranty of any kind,
deba@937:  * express or implied, and with no claim as to its suitability for any
deba@937:  * purpose.
deba@937:  *
deba@937:  */
deba@937: 
deba@937: #ifndef LEMON_SKELETON_SYM_GRAPH_H
deba@937: #define LEMON_SKELETON_SYM_GRAPH_H
deba@937: 
deba@937: ///\ingroup skeletons
deba@937: ///\file
deba@937: ///\brief Declaration of SymGraph.
deba@937: 
deba@937: #include <lemon/invalid.h>
deba@937: #include <lemon/skeletons/graph.h>
deba@937: #include <lemon/skeletons/maps.h>
deba@937: 
deba@937: namespace lemon {
deba@937:   namespace skeleton {
deba@937:     
deba@937:     /// \addtogroup skeletons
deba@937:     /// @{
deba@937: 
deba@937:     /// An empty static graph class.
deba@937:   
deba@937:     /// This class provides all the common features of a symmetric
deba@937:     /// graph structure, however completely without implementations and 
deba@937:     /// real data structures behind the interface.
deba@937:     /// All graph algorithms should compile with this class, but it will not
deba@937:     /// run properly, of course.
deba@937:     ///
deba@937:     /// It can be used for checking the interface compatibility,
deba@937:     /// or it can serve as a skeleton of a new symmetric graph structure.
deba@937:     /// 
deba@937:     /// Also, you will find here the full documentation of a certain graph
deba@937:     /// feature, the documentation of a real symmetric graph imlementation
deba@937:     /// like @ref SymListGraph or
deba@937:     /// @ref lemon::SymSmartGraph will just refer to this structure.
deba@937:     class StaticSymGraph
deba@937:     {
deba@937:     public:
deba@937:       /// Defalult constructor.
deba@937: 
deba@937:       /// Defalult constructor.
deba@937:       ///
deba@937:       StaticSymGraph() { }
deba@937:       ///Copy consructor.
deba@937: 
deba@937: //       ///\todo It is not clear, what we expect from a copy constructor.
deba@937: //       ///E.g. How to assign the nodes/edges to each other? What about maps?
deba@937: //       StaticGraph(const StaticGraph& g) { }
deba@937: 
deba@937:       /// The base type of node iterators, 
deba@937:       /// or in other words, the trivial node iterator.
deba@937: 
deba@937:       /// This is the base type of each node iterator,
deba@937:       /// thus each kind of node iterator converts to this.
deba@937:       /// More precisely each kind of node iterator should be inherited 
deba@937:       /// from the trivial node iterator.
deba@937:       class Node {
deba@937:       public:
deba@937: 	/// Default constructor
deba@937: 
deba@937: 	/// @warning The default constructor sets the iterator
deba@937: 	/// to an undefined value.
deba@937: 	Node() { }
deba@937: 	/// Copy constructor.
deba@937: 
deba@937: 	/// Copy constructor.
deba@937: 	///
deba@937: 	Node(const Node&) { }
deba@937: 
deba@937: 	/// Invalid constructor \& conversion.
deba@937: 
deba@937: 	/// This constructor initializes the iterator to be invalid.
deba@937: 	/// \sa Invalid for more details.
deba@937: 	Node(Invalid) { }
deba@937: 	/// Equality operator
deba@937: 
deba@937: 	/// Two iterators are equal if and only if they point to the
deba@937: 	/// same object or both are invalid.
deba@937: 	bool operator==(Node) const { return true; }
deba@937: 
deba@937: 	/// Inequality operator
deba@937: 	
deba@937: 	/// \sa operator==(Node n)
deba@937: 	///
deba@937: 	bool operator!=(Node) const { return true; }
deba@937: 
deba@937:  	///Comparison operator.
deba@937: 
deba@937: 	///This is a strict ordering between the nodes.
deba@937: 	///
deba@937: 	///This ordering can be different from the order in which NodeIt
deba@937: 	///goes through the nodes.
deba@937: 	///\todo Possibly we don't need it.
deba@937: 	bool operator<(Node) const { return true; }
deba@937:       };
deba@937:     
deba@937:       /// This iterator goes through each node.
deba@937: 
deba@937:       /// This iterator goes through each node.
deba@937:       /// Its usage is quite simple, for example you can count the number
deba@937:       /// of nodes in graph \c g of type \c Graph like this:
deba@937:       /// \code
deba@937:       /// int count=0;
deba@937:       /// for (Graph::NodeIt n(g); n!=INVALID; ++n) ++count;
deba@937:       /// \endcode
deba@937:       class NodeIt : public Node {
deba@937:       public:
deba@937: 	/// Default constructor
deba@937: 
deba@937: 	/// @warning The default constructor sets the iterator
deba@937: 	/// to an undefined value.
deba@937: 	NodeIt() { }
deba@937: 	/// Copy constructor.
deba@937: 	
deba@937: 	/// Copy constructor.
deba@937: 	///
deba@937: 	NodeIt(const NodeIt&) { }
deba@937: 	/// Invalid constructor \& conversion.
deba@937: 
deba@937: 	/// Initialize the iterator to be invalid.
deba@937: 	/// \sa Invalid for more details.
deba@937: 	NodeIt(Invalid) { }
deba@937: 	/// Sets the iterator to the first node.
deba@937: 
deba@937: 	/// Sets the iterator to the first node of \c g.
deba@937: 	///
deba@937: 	NodeIt(const StaticSymGraph& g) { }
deba@937: 	/// Node -> NodeIt conversion.
deba@937: 
deba@937: 	/// Sets the iterator to the node of \c g pointed by the trivial 
deba@937: 	/// iterator n.
deba@937: 	/// This feature necessitates that each time we 
deba@937: 	/// iterate the edge-set, the iteration order is the same.
deba@937: 	NodeIt(const StaticSymGraph& g, const Node& n) { }
deba@937: 	/// Next node.
deba@937: 
deba@937: 	/// Assign the iterator to the next node.
deba@937: 	///
deba@937: 	NodeIt& operator++() { return *this; }
deba@937:       };
deba@937:     
deba@937:     
deba@937:       /// The base type of the symmetric edge iterators.
deba@937: 
deba@937:       /// The base type of the symmetric edge iterators.
deba@937:       ///
deba@937:       class SymEdge {
deba@937:       public:
deba@937: 	/// Default constructor
deba@937: 
deba@937: 	/// @warning The default constructor sets the iterator
deba@937: 	/// to an undefined value.
deba@937: 	SymEdge() { }
deba@937: 	/// Copy constructor.
deba@937: 
deba@937: 	/// Copy constructor.
deba@937: 	///
deba@937: 	SymEdge(const SymEdge&) { }
deba@937: 	/// Initialize the iterator to be invalid.
deba@937: 
deba@937: 	/// Initialize the iterator to be invalid.
deba@937: 	///
deba@937: 	SymEdge(Invalid) { }
deba@937: 	/// Equality operator
deba@937: 
deba@937: 	/// Two iterators are equal if and only if they point to the
deba@937: 	/// same object or both are invalid.
deba@937: 	bool operator==(SymEdge) const { return true; }
deba@937: 	/// Inequality operator
deba@937: 
deba@937: 	/// \sa operator==(Node n)
deba@937: 	///
deba@937: 	bool operator!=(SymEdge) const { return true; }
deba@937:  	///Comparison operator.
deba@937: 
deba@937: 	///This is a strict ordering between the nodes.
deba@937: 	///
deba@937: 	///This ordering can be different from the order in which NodeIt
deba@937: 	///goes through the nodes.
deba@937: 	///\todo Possibly we don't need it.
deba@937:  	bool operator<(SymEdge) const { return true; }
deba@937:       };
deba@937: 
deba@937: 
deba@937:       /// The base type of the edge iterators.
deba@937: 
deba@937:       /// The base type of the edge iterators.
deba@937:       ///
deba@937:       class Edge : public SymEdge {
deba@937:       public:
deba@937: 	/// Default constructor
deba@937: 
deba@937: 	/// @warning The default constructor sets the iterator
deba@937: 	/// to an undefined value.
deba@937: 	Edge() { }
deba@937: 	/// Copy constructor.
deba@937: 
deba@937: 	/// Copy constructor.
deba@937: 	///
deba@937: 	Edge(const Edge&) { }
deba@937: 	/// Initialize the iterator to be invalid.
deba@937: 
deba@937: 	/// Initialize the iterator to be invalid.
deba@937: 	///
deba@937: 	Edge(Invalid) { }
deba@937: 	/// Equality operator
deba@937: 
deba@937: 	/// Two iterators are equal if and only if they point to the
deba@937: 	/// same object or both are invalid.
deba@937: 	bool operator==(Edge) const { return true; }
deba@937: 	/// Inequality operator
deba@937: 
deba@937: 	/// \sa operator==(Node n)
deba@937: 	///
deba@937: 	bool operator!=(Edge) const { return true; }
deba@937:  	///Comparison operator.
deba@937: 
deba@937: 	///This is a strict ordering between the nodes.
deba@937: 	///
deba@937: 	///This ordering can be different from the order in which NodeIt
deba@937: 	///goes through the nodes.
deba@937: 	///\todo Possibly we don't need it.
deba@937:  	bool operator<(Edge) const { return true; }
deba@937:       };
deba@937:     
deba@937:       /// This iterator goes trough the outgoing edges of a node.
deba@937: 
deba@937:       /// This iterator goes trough the \e outgoing edges of a certain node
deba@937:       /// of a graph.
deba@937:       /// Its usage is quite simple, for example you can count the number
deba@937:       /// of outgoing edges of a node \c n
deba@937:       /// in graph \c g of type \c Graph as follows.
deba@937:       /// \code
deba@937:       /// int count=0;
deba@937:       /// for (Graph::OutEdgeIt e(g, n); e!=INVALID; ++e) ++count;
deba@937:       /// \endcode
deba@937:     
deba@937:       class OutEdgeIt : public Edge {
deba@937:       public:
deba@937: 	/// Default constructor
deba@937: 
deba@937: 	/// @warning The default constructor sets the iterator
deba@937: 	/// to an undefined value.
deba@937: 	OutEdgeIt() { }
deba@937: 	/// Copy constructor.
deba@937: 
deba@937: 	/// Copy constructor.
deba@937: 	///
deba@937: 	OutEdgeIt(const OutEdgeIt&) { }
deba@937: 	/// Initialize the iterator to be invalid.
deba@937: 
deba@937: 	/// Initialize the iterator to be invalid.
deba@937: 	///
deba@937: 	OutEdgeIt(Invalid) { }
deba@937: 	/// This constructor sets the iterator to first outgoing edge.
deba@937:     
deba@937: 	/// This constructor set the iterator to the first outgoing edge of
deba@937: 	/// node
deba@937: 	///@param n the node
deba@937: 	///@param g the graph
deba@937: 	OutEdgeIt(const StaticSymGraph& g, const Node& n) { }
deba@937: 	/// Edge -> OutEdgeIt conversion
deba@937: 
deba@937: 	/// Sets the iterator to the value of the trivial iterator \c e.
deba@937: 	/// This feature necessitates that each time we 
deba@937: 	/// iterate the edge-set, the iteration order is the same.
deba@937: 	OutEdgeIt(const StaticSymGraph& g, const Edge& e) { }
deba@937: 	///Next outgoing edge
deba@937: 	
deba@937: 	/// Assign the iterator to the next 
deba@937: 	/// outgoing edge of the corresponding node.
deba@937: 	OutEdgeIt& operator++() { return *this; }
deba@937:       };
deba@937: 
deba@937:       /// This iterator goes trough the incoming edges of a node.
deba@937: 
deba@937:       /// This iterator goes trough the \e incoming edges of a certain node
deba@937:       /// of a graph.
deba@937:       /// Its usage is quite simple, for example you can count the number
deba@937:       /// of outgoing edges of a node \c n
deba@937:       /// in graph \c g of type \c Graph as follows.
deba@937:       /// \code
deba@937:       /// int count=0;
deba@937:       /// for(Graph::InEdgeIt e(g, n); e!=INVALID; ++e) ++count;
deba@937:       /// \endcode
deba@937: 
deba@937:       class InEdgeIt : public Edge {
deba@937:       public:
deba@937: 	/// Default constructor
deba@937: 
deba@937: 	/// @warning The default constructor sets the iterator
deba@937: 	/// to an undefined value.
deba@937: 	InEdgeIt() { }
deba@937: 	/// Copy constructor.
deba@937: 
deba@937: 	/// Copy constructor.
deba@937: 	///
deba@937: 	InEdgeIt(const InEdgeIt&) { }
deba@937: 	/// Initialize the iterator to be invalid.
deba@937: 
deba@937: 	/// Initialize the iterator to be invalid.
deba@937: 	///
deba@937: 	InEdgeIt(Invalid) { }
deba@937: 	/// This constructor sets the iterator to first incoming edge.
deba@937:     
deba@937: 	/// This constructor set the iterator to the first incoming edge of
deba@937: 	/// node
deba@937: 	///@param n the node
deba@937: 	///@param g the graph
deba@937: 	InEdgeIt(const StaticSymGraph& g, const Node& n) { }
deba@937: 	/// Edge -> InEdgeIt conversion
deba@937: 
deba@937: 	/// Sets the iterator to the value of the trivial iterator \c e.
deba@937: 	/// This feature necessitates that each time we 
deba@937: 	/// iterate the edge-set, the iteration order is the same.
deba@937: 	InEdgeIt(const StaticSymGraph& g, const Edge& n) { }
deba@937: 	/// Next incoming edge
deba@937: 
deba@937: 	/// Assign the iterator to the next inedge of the corresponding node.
deba@937: 	///
deba@937: 	InEdgeIt& operator++() { return *this; }
deba@937:       };
deba@937:       /// This iterator goes through each symmetric edge.
deba@937: 
deba@937:       /// This iterator goes through each symmetric edge of a graph.
deba@937:       /// Its usage is quite simple, for example you can count the number
deba@937:       /// of symmetric edges in a graph \c g of type \c Graph as follows:
deba@937:       /// \code
deba@937:       /// int count=0;
deba@937:       /// for(Graph::SymEdgeIt e(g); e!=INVALID; ++e) ++count;
deba@937:       /// \endcode
deba@937:       class SymEdgeIt : public SymEdge {
deba@937:       public:
deba@937: 	/// Default constructor
deba@937: 
deba@937: 	/// @warning The default constructor sets the iterator
deba@937: 	/// to an undefined value.
deba@937: 	SymEdgeIt() { }
deba@937: 	/// Copy constructor.
deba@937: 
deba@937: 	/// Copy constructor.
deba@937: 	///
deba@937: 	SymEdgeIt(const SymEdgeIt&) { }
deba@937: 	/// Initialize the iterator to be invalid.
deba@937: 
deba@937: 	/// Initialize the iterator to be invalid.
deba@937: 	///
deba@937: 	SymEdgeIt(Invalid) { }
deba@937: 	/// This constructor sets the iterator to first edge.
deba@937:     
deba@937: 	/// This constructor set the iterator to the first edge of
deba@937: 	/// node
deba@937: 	///@param g the graph
deba@937: 	SymEdgeIt(const StaticSymGraph& g) { }
deba@937: 	/// Edge -> EdgeIt conversion
deba@937: 
deba@937: 	/// Sets the iterator to the value of the trivial iterator \c e.
deba@937: 	/// This feature necessitates that each time we 
deba@937: 	/// iterate the edge-set, the iteration order is the same.
deba@937: 	SymEdgeIt(const StaticSymGraph&, const SymEdge&) { } 
deba@937:     	///Next edge
deba@937: 	
deba@937: 	/// Assign the iterator to the next 
deba@937: 	/// edge of the corresponding node.
deba@937: 	SymEdgeIt& operator++() { return *this; }
deba@937:       };
deba@937:       /// This iterator goes through each edge.
deba@937: 
deba@937:       /// This iterator goes through each edge of a graph.
deba@937:       /// Its usage is quite simple, for example you can count the number
deba@937:       /// of edges in a graph \c g of type \c Graph as follows:
deba@937:       /// \code
deba@937:       /// int count=0;
deba@937:       /// for(Graph::EdgeIt e(g); e!=INVALID; ++e) ++count;
deba@937:       /// \endcode
deba@937:       class EdgeIt : public Edge {
deba@937:       public:
deba@937: 	/// Default constructor
deba@937: 
deba@937: 	/// @warning The default constructor sets the iterator
deba@937: 	/// to an undefined value.
deba@937: 	EdgeIt() { }
deba@937: 	/// Copy constructor.
deba@937: 
deba@937: 	/// Copy constructor.
deba@937: 	///
deba@937: 	EdgeIt(const EdgeIt&) { }
deba@937: 	/// Initialize the iterator to be invalid.
deba@937: 
deba@937: 	/// Initialize the iterator to be invalid.
deba@937: 	///
deba@937: 	EdgeIt(Invalid) { }
deba@937: 	/// This constructor sets the iterator to first edge.
deba@937:     
deba@937: 	/// This constructor set the iterator to the first edge of
deba@937: 	/// node
deba@937: 	///@param g the graph
deba@937: 	EdgeIt(const StaticSymGraph& g) { }
deba@937: 	/// Edge -> EdgeIt conversion
deba@937: 
deba@937: 	/// Sets the iterator to the value of the trivial iterator \c e.
deba@937: 	/// This feature necessitates that each time we 
deba@937: 	/// iterate the edge-set, the iteration order is the same.
deba@937: 	EdgeIt(const StaticSymGraph&, const Edge&) { } 
deba@937:     	///Next edge
deba@937: 	
deba@937: 	/// Assign the iterator to the next 
deba@937: 	/// edge of the corresponding node.
deba@937: 	EdgeIt& operator++() { return *this; }
deba@937:       };
deba@937: 
deba@937:       /// First node of the graph.
deba@937: 
deba@937:       /// \retval i the first node.
deba@937:       /// \return the first node.
deba@937:       ///
deba@937:       NodeIt& first(NodeIt& i) const { return i; }
deba@937: 
deba@937:       /// The first incoming edge.
deba@937: 
deba@937:       /// The first incoming edge.
deba@937:       ///
deba@937:       InEdgeIt& first(InEdgeIt &i, Node) const { return i; }
deba@937:       /// The first outgoing edge.
deba@937: 
deba@937:       /// The first outgoing edge.
deba@937:       ///
deba@937:       OutEdgeIt& first(OutEdgeIt& i, Node) const { return i; }
deba@937:       /// The first edge of the Graph.
deba@937: 
deba@937:       /// The first edge of the Graph.
deba@937:       ///
deba@937:       EdgeIt& first(EdgeIt& i) const { return i; }
deba@937:       /// The first symmetric edge of the Graph.
deba@937: 
deba@937:       /// The first symmetric edge of the Graph.
deba@937:       ///
deba@937:       SymEdgeIt& first(SymEdgeIt& i) const { return i; }
deba@937: 
deba@937:       ///Gives back the head node of an edge.
deba@937: 
deba@937:       ///Gives back the head node of an edge.
deba@937:       ///
deba@937:       Node head(Edge) const { return INVALID; }
deba@937:       ///Gives back the tail node of an edge.
deba@937: 
deba@937:       ///Gives back the tail node of an edge.
deba@937:       ///
deba@937:       Node tail(Edge) const { return INVALID; }
deba@937:   
deba@937:       ///Gives back the first node of an symmetric edge.
deba@937: 
deba@937:       ///Gives back the first node of an symmetric edge.
deba@937:       ///
deba@937:       Node head(SymEdge) const { return INVALID; }
deba@937:       ///Gives back the second node of an symmetric edge.
deba@937: 
deba@937:       ///Gives back the second node of an symmetric edge.
deba@937:       ///
deba@937:       Node tail(SymEdge) const { return INVALID; }
deba@937:       ///Gives back the \e id of a node.
deba@937: 
deba@937:       ///\warning Not all graph structures provide this feature.
deba@937:       ///
deba@937:       ///\todo Should each graph provide \c id?
deba@937:       int id(const Node&) const { return 0; }
deba@937:       ///Gives back the \e id of an edge.
deba@937: 
deba@937:       ///\warning Not all graph structures provide this feature.
deba@937:       ///
deba@937:       ///\todo Should each graph provide \c id?
deba@937:       int id(const Edge&) const { return 0; }
deba@937: 
deba@937:       ///\warning Not all graph structures provide this feature.
deba@937:       ///
deba@937:       ///\todo Should each graph provide \c id?
deba@937:       int id(const SymEdge&) const { return 0; }
deba@937: 
deba@937:       ///\e
deba@937:       
deba@937:       ///\todo Should it be in the concept?
deba@937:       ///
deba@937:       int nodeNum() const { return 0; }
deba@937:       ///\e
deba@937: 
deba@937:       ///\todo Should it be in the concept?
deba@937:       ///
deba@937:       int edgeNum() const { return 0; }
deba@937: 
deba@937:       ///\todo Should it be in the concept?
deba@937:       ///
deba@937:       int symEdgeNum() const { return 0; }
deba@937: 
deba@937: 
deba@937:       /// Gives back the forward directed edge of the symmetric edge.
deba@937:       Edge forward(SymEdge) const {return INVALID;} 
deba@937: 
deba@937:       /// Gives back the backward directed edge of the symmetric edge.
deba@937:       Edge backward(SymEdge) const {return INVALID;};
deba@937: 
deba@937:       /// Gives back the opposite of the edge.
deba@937:       Edge opposite(Edge) const {return INVALID;}
deba@937: 
deba@937:       ///Reference map of the nodes to type \c T.
deba@937:       /// \ingroup skeletons
deba@937:       ///Reference map of the nodes to type \c T.
deba@937:       /// \sa Reference
deba@937:       /// \warning Making maps that can handle bool type (NodeMap<bool>)
deba@937:       /// needs some extra attention!
deba@937:       template<class T> class NodeMap : public ReferenceMap< Node, T >
deba@937:       {
deba@937:       public:
deba@937: 
deba@937: 	///\e
deba@937: 	NodeMap(const StaticSymGraph&) { }
deba@937: 	///\e
deba@937: 	NodeMap(const StaticSymGraph&, T) { }
deba@937: 
deba@937: 	///Copy constructor
deba@937: 	template<typename TT> NodeMap(const NodeMap<TT>&) { }
deba@937: 	///Assignment operator
deba@937: 	template<typename TT> NodeMap& operator=(const NodeMap<TT>&)
deba@937: 	{ return *this; }
deba@937:       };
deba@937: 
deba@937:       ///Reference map of the edges to type \c T.
deba@937: 
deba@937:       /// \ingroup skeletons
deba@937:       ///Reference map of the edges to type \c T.
deba@937:       /// \sa Reference
deba@937:       /// \warning Making maps that can handle bool type (EdgeMap<bool>)
deba@937:       /// needs some extra attention!
deba@937:       template<class T> class EdgeMap
deba@937: 	: public ReferenceMap<Edge,T>
deba@937:       {
deba@937:       public:
deba@937: 
deba@937: 	///\e
deba@937: 	EdgeMap(const StaticSymGraph&) { }
deba@937: 	///\e
deba@937: 	EdgeMap(const StaticSymGraph&, T) { }
deba@937:     
deba@937: 	///Copy constructor
deba@937: 	template<typename TT> EdgeMap(const EdgeMap<TT>&) { }
deba@937: 	///Assignment operator
deba@937: 	template<typename TT> EdgeMap &operator=(const EdgeMap<TT>&)
deba@937: 	{ return *this; }
deba@937:       };
deba@937: 
deba@937:       ///Reference map of the edges to type \c T.
deba@937: 
deba@937:       /// \ingroup skeletons
deba@937:       ///Reference map of the symmetric edges to type \c T.
deba@937:       /// \sa Reference
deba@937:       /// \warning Making maps that can handle bool type (EdgeMap<bool>)
deba@937:       /// needs some extra attention!
deba@937:       template<class T> class SymEdgeMap
deba@937: 	: public ReferenceMap<SymEdge,T>
deba@937:       {
deba@937:       public:
deba@937: 
deba@937: 	///\e
deba@937: 	SymEdgeMap(const StaticSymGraph&) { }
deba@937: 	///\e
deba@937: 	SymEdgeMap(const StaticSymGraph&, T) { }
deba@937:     
deba@937: 	///Copy constructor
deba@937: 	template<typename TT> SymEdgeMap(const SymEdgeMap<TT>&) { }
deba@937: 	///Assignment operator
deba@937: 	template<typename TT> SymEdgeMap &operator=(const SymEdgeMap<TT>&)
deba@937: 	{ return *this; }
deba@937:       };
deba@937:     };
deba@937: 
deba@937: 
deba@937:   
deba@937:     /// An empty non-static graph class.
deba@937: 
deba@937:     /// This class provides everything that \ref StaticGraph
deba@937:     /// with additional functionality which enables to build a
deba@937:     /// graph from scratch.
deba@937:     class ExtendableSymGraph : public StaticSymGraph
deba@937:     {
deba@937:     public:
deba@937:       /// Defalult constructor.
deba@937: 
deba@937:       /// Defalult constructor.
deba@937:       ///
deba@937:       ExtendableSymGraph() { }
deba@937:       ///Add a new node to the graph.
deba@937: 
deba@937:       /// \return the new node.
deba@937:       ///
deba@937:       Node addNode() { return INVALID; }
deba@937:       ///Add a new edge to the graph.
deba@937: 
deba@937:       ///Add a new symmetric edge to the graph with tail node \c t
deba@937:       ///and head node \c h.
deba@937:       ///\return the new edge.
deba@937:       SymEdge addEdge(Node h, Node t) { return INVALID; }
deba@937:     
deba@937:       /// Resets the graph.
deba@937: 
deba@937:       /// This function deletes all edges and nodes of the graph.
deba@937:       /// It also frees the memory allocated to store them.
deba@937:       /// \todo It might belong to \ref ErasableGraph.
deba@937:       void clear() { }
deba@937:     };
deba@937: 
deba@937:     /// An empty erasable graph class.
deba@937:   
deba@937:     /// This class is an extension of \ref ExtendableGraph. It also makes it
deba@937:     /// possible to erase edges or nodes.
deba@937:     class ErasableSymGraph : public ExtendableSymGraph
deba@937:     {
deba@937:     public:
deba@937:       /// Defalult constructor.
deba@937: 
deba@937:       /// Defalult constructor.
deba@937:       ///
deba@937:       ErasableSymGraph() { }
deba@937:       /// Deletes a node.
deba@937: 
deba@937:       /// Deletes node \c n node.
deba@937:       ///
deba@937:       void erase(Node n) { }
deba@937:       /// Deletes an edge.
deba@937: 
deba@937:       /// Deletes edge \c e edge.
deba@937:       ///
deba@937:       void erase(SymEdge e) { }
deba@937:     };
deba@937: 
deba@937:     // @}
deba@937:   } //namespace skeleton  
deba@937: } //namespace lemon
deba@937: 
deba@937: 
deba@937: 
deba@937: #endif // LEMON_SKELETON_GRAPH_H