src/lemon/concept/graph.h
changeset 1431 ad44b1dd8013
parent 1367 a490662291b9
equal deleted inserted replaced
9:6330f3c92b2d 10:f78244d75571
    34     /// @{
    34     /// @{
    35 
    35 
    36     /**************** The full-featured graph concepts ****************/
    36     /**************** The full-featured graph concepts ****************/
    37 
    37 
    38 
    38 
    39     /// \brief Modular builded static graph class.
    39     /// \brief Modular static graph class.
    40     ///     
    40     ///     
    41     /// It should be the same as the \c StaticGraph class.
    41     /// It should be the same as the \c StaticGraph class.
    42     class _StaticGraph 
    42     class _StaticGraph 
    43       :  virtual public BaseGraphComponent,
    43       :  virtual public BaseGraphComponent,
    44 	 public IterableGraphComponent, public MappableGraphComponent {
    44          public IterableGraphComponent, public MappableGraphComponent {
    45     public:
    45     public:
    46       typedef BaseGraphComponent::Node Node;
    46       typedef BaseGraphComponent::Node Node;
    47       typedef BaseGraphComponent::Edge Edge;
    47       typedef BaseGraphComponent::Edge Edge;
    48 
    48 
    49       template <typename _Graph>
    49       template <typename _Graph>
    50       struct Constraints {
    50       struct Constraints {
    51 	void constraints() {
    51         void constraints() {
    52 	  checkConcept<IterableGraphComponent, _Graph>();
    52           checkConcept<IterableGraphComponent, _Graph>();
    53 	  checkConcept<MappableGraphComponent, _Graph>();
    53           checkConcept<MappableGraphComponent, _Graph>();
    54 	}
    54         }
    55       };
    55       };
    56     };
    56     };
    57 
    57 
    58     /// \brief Modular builded extendable graph class.
    58     /// \brief Modular extendable graph class.
    59     ///     
    59     ///     
    60     /// It should be the same as the \c ExtendableGraph class.
    60     /// It should be the same as the \c ExtendableGraph class.
    61     class _ExtendableGraph 
    61     class _ExtendableGraph 
    62       :  virtual public BaseGraphComponent, public _StaticGraph,
    62       :  virtual public BaseGraphComponent, public _StaticGraph,
    63 	 public ExtendableGraphComponent, public ClearableGraphComponent {
    63          public ExtendableGraphComponent, public ClearableGraphComponent {
    64     public:
    64     public:
    65       typedef BaseGraphComponent::Node Node;
    65       typedef BaseGraphComponent::Node Node;
    66       typedef BaseGraphComponent::Edge Edge;
    66       typedef BaseGraphComponent::Edge Edge;
    67 
    67 
    68       template <typename _Graph>
    68       template <typename _Graph>
    69       struct Constraints {
    69       struct Constraints {
    70 	void constraints() {
    70         void constraints() {
    71 	  checkConcept<_StaticGraph, _Graph >();
    71           checkConcept<_StaticGraph, _Graph >();
    72 	  checkConcept<ExtendableGraphComponent, _Graph >();
    72           checkConcept<ExtendableGraphComponent, _Graph >();
    73 	  checkConcept<ClearableGraphComponent, _Graph >();
    73           checkConcept<ClearableGraphComponent, _Graph >();
    74 	}
    74         }
    75       };
    75       };
    76     };
    76     };
    77 
    77 
    78     /// \brief Modular builded erasable graph class.
    78     /// \brief Modular erasable graph class.
    79     ///     
    79     ///     
    80     /// It should be the same as the \c ErasableGraph class.
    80     /// It should be the same as the \c ErasableGraph class.
    81     class _ErasableGraph 
    81     class _ErasableGraph 
    82       :  virtual public BaseGraphComponent, public _ExtendableGraph,
    82       :  virtual public BaseGraphComponent, public _ExtendableGraph,
    83 	 public ErasableGraphComponent {
    83          public ErasableGraphComponent {
    84     public:
    84     public:
    85       typedef BaseGraphComponent::Node Node;
    85       typedef BaseGraphComponent::Node Node;
    86       typedef BaseGraphComponent::Edge Edge;
    86       typedef BaseGraphComponent::Edge Edge;
    87 
    87 
    88       template <typename _Graph>
    88       template <typename _Graph>
    89       struct Constraints {
    89       struct Constraints {
    90 	void constraints() {
    90         void constraints() {
    91 	  checkConcept<_ExtendableGraph, _Graph >();
    91           checkConcept<_ExtendableGraph, _Graph >();
    92 	  checkConcept<ErasableGraphComponent, _Graph >();
    92           checkConcept<ErasableGraphComponent, _Graph >();
    93 	}
    93         }
    94       };
    94       };
    95     };
    95     };
    96 
    96 
    97     /// An empty static graph class.
    97     /// An empty static graph class.
    98   
    98   
   133       /// thus each kind of node iterator converts to this.
   133       /// thus each kind of node iterator converts to this.
   134       /// More precisely each kind of node iterator should be inherited 
   134       /// More precisely each kind of node iterator should be inherited 
   135       /// from the trivial node iterator.
   135       /// from the trivial node iterator.
   136       class Node {
   136       class Node {
   137       public:
   137       public:
   138 	/// Default constructor
   138         /// Default constructor
   139 
   139 
   140 	/// @warning The default constructor sets the iterator
   140         /// @warning The default constructor sets the iterator
   141 	/// to an undefined value.
   141         /// to an undefined value.
   142 	Node() { }
   142         Node() { }
   143 	/// Copy constructor.
   143         /// Copy constructor.
   144 
   144 
   145 	/// Copy constructor.
   145         /// Copy constructor.
   146 	///
   146         ///
   147 	Node(const Node&) { }
   147         Node(const Node&) { }
   148 
   148 
   149 	/// Invalid constructor \& conversion.
   149         /// Invalid constructor \& conversion.
   150 
   150 
   151 	/// This constructor initializes the iterator to be invalid.
   151         /// This constructor initializes the iterator to be invalid.
   152 	/// \sa Invalid for more details.
   152         /// \sa Invalid for more details.
   153 	Node(Invalid) { }
   153         Node(Invalid) { }
   154 	/// Equality operator
   154         /// Equality operator
   155 
   155 
   156 	/// Two iterators are equal if and only if they point to the
   156         /// Two iterators are equal if and only if they point to the
   157 	/// same object or both are invalid.
   157         /// same object or both are invalid.
   158 	bool operator==(Node) const { return true; }
   158         bool operator==(Node) const { return true; }
   159 
   159 
   160 	/// Inequality operator
   160         /// Inequality operator
   161 	
   161         
   162 	/// \sa operator==(Node n)
   162         /// \sa operator==(Node n)
   163 	///
   163         ///
   164 	bool operator!=(Node) const { return true; }
   164         bool operator!=(Node) const { return true; }
   165 
   165 
   166       };
   166       };
   167     
   167     
   168       /// This iterator goes through each node.
   168       /// This iterator goes through each node.
   169 
   169 
   170       /// This iterator goes through each node.
   170       /// This iterator goes through each node.
   171       /// Its usage is quite simple, for example you can count the number
   171       /// Its usage is quite simple, for example you can count the number
   172       /// of nodes in graph \c g of type \c Graph like this:
   172       /// of nodes in graph \c g of type \c Graph like this:
   173       /// \code
   173       /// \code
   174       /// int count=0;
   174       /// int count=0;
   175       /// for (Graph::NodeIt n(g); n!=INVALID ++n) ++count;
   175       /// for (Graph::NodeIt n(g); n!=INVALID; ++n) ++count;
   176       /// \endcode
   176       /// \endcode
   177       class NodeIt : public Node {
   177       class NodeIt : public Node {
   178       public:
   178       public:
   179 	/// Default constructor
   179         /// Default constructor
   180 
   180 
   181 	/// @warning The default constructor sets the iterator
   181         /// @warning The default constructor sets the iterator
   182 	/// to an undefined value.
   182         /// to an undefined value.
   183 	NodeIt() { }
   183         NodeIt() { }
   184 	/// Copy constructor.
   184         /// Copy constructor.
   185 	
   185         
   186 	/// Copy constructor.
   186         /// Copy constructor.
   187 	///
   187         ///
   188 	NodeIt(const NodeIt& n) : Node(n) { }
   188         NodeIt(const NodeIt& n) : Node(n) { }
   189 	/// Invalid constructor \& conversion.
   189         /// Invalid constructor \& conversion.
   190 
   190 
   191 	/// Initialize the iterator to be invalid.
   191         /// Initialize the iterator to be invalid.
   192 	/// \sa Invalid for more details.
   192         /// \sa Invalid for more details.
   193 	NodeIt(Invalid) { }
   193         NodeIt(Invalid) { }
   194 	/// Sets the iterator to the first node.
   194         /// Sets the iterator to the first node.
   195 
   195 
   196 	/// Sets the iterator to the first node of \c g.
   196         /// Sets the iterator to the first node of \c g.
   197 	///
   197         ///
   198 	NodeIt(const StaticGraph&) { }
   198         NodeIt(const StaticGraph&) { }
   199 	/// Node -> NodeIt conversion.
   199         /// Node -> NodeIt conversion.
   200 
   200 
   201 	/// Sets the iterator to the node of \c g pointed by the trivial 
   201         /// Sets the iterator to the node of \c g pointed by the trivial 
   202 	/// iterator n.
   202         /// iterator n.
   203 	/// This feature necessitates that each time we 
   203         /// This feature necessitates that each time we 
   204 	/// iterate the edge-set, the iteration order is the same.
   204         /// iterate the edge-set, the iteration order is the same.
   205 	NodeIt(const StaticGraph& g, const Node& n) { }
   205         NodeIt(const StaticGraph& g, const Node& n) { }
   206 	/// Next node.
   206         /// Next node.
   207 
   207 
   208 	/// Assign the iterator to the next node.
   208         /// Assign the iterator to the next node.
   209 	///
   209         ///
   210 	NodeIt& operator++() { return *this; }
   210         NodeIt& operator++() { return *this; }
   211       };
   211       };
   212     
   212     
   213     
   213     
   214       /// The base type of the edge iterators.
   214       /// The base type of the edge iterators.
   215 
   215 
   216       /// The base type of the edge iterators.
   216       /// The base type of the edge iterators.
   217       ///
   217       ///
   218       class Edge {
   218       class Edge {
   219       public:
   219       public:
   220 	/// Default constructor
   220         /// Default constructor
   221 
   221 
   222 	/// @warning The default constructor sets the iterator
   222         /// @warning The default constructor sets the iterator
   223 	/// to an undefined value.
   223         /// to an undefined value.
   224 	Edge() { }
   224         Edge() { }
   225 	/// Copy constructor.
   225         /// Copy constructor.
   226 
   226 
   227 	/// Copy constructor.
   227         /// Copy constructor.
   228 	///
   228         ///
   229 	Edge(const Edge&) { }
   229         Edge(const Edge&) { }
   230 	/// Initialize the iterator to be invalid.
   230         /// Initialize the iterator to be invalid.
   231 
   231 
   232 	/// Initialize the iterator to be invalid.
   232         /// Initialize the iterator to be invalid.
   233 	///
   233         ///
   234 	Edge(Invalid) { }
   234         Edge(Invalid) { }
   235 	/// Equality operator
   235         /// Equality operator
   236 
   236 
   237 	/// Two iterators are equal if and only if they point to the
   237         /// Two iterators are equal if and only if they point to the
   238 	/// same object or both are invalid.
   238         /// same object or both are invalid.
   239 	bool operator==(Edge) const { return true; }
   239         bool operator==(Edge) const { return true; }
   240 	/// Inequality operator
   240         /// Inequality operator
   241 
   241 
   242 	/// \sa operator==(Node n)
   242         /// \sa operator==(Node n)
   243 	///
   243         ///
   244 	bool operator!=(Edge) const { return true; }
   244         bool operator!=(Edge) const { return true; }
   245       };
   245       };
   246     
   246     
   247       /// This iterator goes trough the outgoing edges of a node.
   247       /// This iterator goes trough the outgoing edges of a node.
   248 
   248 
   249       /// This iterator goes trough the \e outgoing edges of a certain node
   249       /// This iterator goes trough the \e outgoing edges of a certain node
   256       /// for (Graph::OutEdgeIt e(g, n); e!=INVALID; ++e) ++count;
   256       /// for (Graph::OutEdgeIt e(g, n); e!=INVALID; ++e) ++count;
   257       /// \endcode
   257       /// \endcode
   258     
   258     
   259       class OutEdgeIt : public Edge {
   259       class OutEdgeIt : public Edge {
   260       public:
   260       public:
   261 	/// Default constructor
   261         /// Default constructor
   262 
   262 
   263 	/// @warning The default constructor sets the iterator
   263         /// @warning The default constructor sets the iterator
   264 	/// to an undefined value.
   264         /// to an undefined value.
   265 	OutEdgeIt() { }
   265         OutEdgeIt() { }
   266 	/// Copy constructor.
   266         /// Copy constructor.
   267 
   267 
   268 	/// Copy constructor.
   268         /// Copy constructor.
   269 	///
   269         ///
   270 	OutEdgeIt(const OutEdgeIt& e) : Edge(e) { }
   270         OutEdgeIt(const OutEdgeIt& e) : Edge(e) { }
   271 	/// Initialize the iterator to be invalid.
   271         /// Initialize the iterator to be invalid.
   272 
   272 
   273 	/// Initialize the iterator to be invalid.
   273         /// Initialize the iterator to be invalid.
   274 	///
   274         ///
   275 	OutEdgeIt(Invalid) { }
   275         OutEdgeIt(Invalid) { }
   276 	/// This constructor sets the iterator to first outgoing edge.
   276         /// This constructor sets the iterator to the first outgoing edge.
   277     
   277     
   278 	/// This constructor set the iterator to the first outgoing edge of
   278         /// This constructor sets the iterator to the first outgoing edge of
   279 	/// node
   279         /// the node.
   280 	///@param n the node
   280         ///@param n the node
   281 	///@param g the graph
   281         ///@param g the graph
   282 	OutEdgeIt(const StaticGraph&, const Node&) { }
   282         OutEdgeIt(const StaticGraph&, const Node&) { }
   283 	/// Edge -> OutEdgeIt conversion
   283         /// Edge -> OutEdgeIt conversion
   284 
   284 
   285 	/// Sets the iterator to the value of the trivial iterator \c e.
   285         /// Sets the iterator to the value of the trivial iterator \c e.
   286 	/// This feature necessitates that each time we 
   286         /// This feature necessitates that each time we 
   287 	/// iterate the edge-set, the iteration order is the same.
   287         /// iterate the edge-set, the iteration order is the same.
   288 	OutEdgeIt(const StaticGraph& g, const Edge& e) { }
   288         OutEdgeIt(const StaticGraph& g, const Edge& e) { }
   289 	///Next outgoing edge
   289         ///Next outgoing edge
   290 	
   290         
   291 	/// Assign the iterator to the next 
   291         /// Assign the iterator to the next 
   292 	/// outgoing edge of the corresponding node.
   292         /// outgoing edge of the corresponding node.
   293 	OutEdgeIt& operator++() { return *this; }
   293         OutEdgeIt& operator++() { return *this; }
   294       };
   294       };
   295 
   295 
   296       /// This iterator goes trough the incoming edges of a node.
   296       /// This iterator goes trough the incoming edges of a node.
   297 
   297 
   298       /// This iterator goes trough the \e incoming edges of a certain node
   298       /// This iterator goes trough the \e incoming edges of a certain node
   305       /// for(Graph::InEdgeIt e(g, n); e!=INVALID; ++e) ++count;
   305       /// for(Graph::InEdgeIt e(g, n); e!=INVALID; ++e) ++count;
   306       /// \endcode
   306       /// \endcode
   307 
   307 
   308       class InEdgeIt : public Edge {
   308       class InEdgeIt : public Edge {
   309       public:
   309       public:
   310 	/// Default constructor
   310         /// Default constructor
   311 
   311 
   312 	/// @warning The default constructor sets the iterator
   312         /// @warning The default constructor sets the iterator
   313 	/// to an undefined value.
   313         /// to an undefined value.
   314 	InEdgeIt() { }
   314         InEdgeIt() { }
   315 	/// Copy constructor.
   315         /// Copy constructor.
   316 
   316 
   317 	/// Copy constructor.
   317         /// Copy constructor.
   318 	///
   318         ///
   319 	InEdgeIt(const InEdgeIt& e) : Edge(e) { }
   319         InEdgeIt(const InEdgeIt& e) : Edge(e) { }
   320 	/// Initialize the iterator to be invalid.
   320         /// Initialize the iterator to be invalid.
   321 
   321 
   322 	/// Initialize the iterator to be invalid.
   322         /// Initialize the iterator to be invalid.
   323 	///
   323         ///
   324 	InEdgeIt(Invalid) { }
   324         InEdgeIt(Invalid) { }
   325 	/// This constructor sets the iterator to first incoming edge.
   325         /// This constructor sets the iterator to first incoming edge.
   326     
   326     
   327 	/// This constructor set the iterator to the first incoming edge of
   327         /// This constructor set the iterator to the first incoming edge of
   328 	/// node
   328         /// the node.
   329 	///@param n the node
   329         ///@param n the node
   330 	///@param g the graph
   330         ///@param g the graph
   331 	InEdgeIt(const StaticGraph&, const Node&) { }
   331         InEdgeIt(const StaticGraph&, const Node&) { }
   332 	/// Edge -> InEdgeIt conversion
   332         /// Edge -> InEdgeIt conversion
   333 
   333 
   334 	/// Sets the iterator to the value of the trivial iterator \c e.
   334         /// Sets the iterator to the value of the trivial iterator \c e.
   335 	/// This feature necessitates that each time we 
   335         /// This feature necessitates that each time we 
   336 	/// iterate the edge-set, the iteration order is the same.
   336         /// iterate the edge-set, the iteration order is the same.
   337 	InEdgeIt(const StaticGraph&, const Edge&) { }
   337         InEdgeIt(const StaticGraph&, const Edge&) { }
   338 	/// Next incoming edge
   338         /// Next incoming edge
   339 
   339 
   340 	/// Assign the iterator to the next inedge of the corresponding node.
   340         /// Assign the iterator to the next inedge of the corresponding node.
   341 	///
   341         ///
   342 	InEdgeIt& operator++() { return *this; }
   342         InEdgeIt& operator++() { return *this; }
   343       };
   343       };
   344       /// This iterator goes through each edge.
   344       /// This iterator goes through each edge.
   345 
   345 
   346       /// This iterator goes through each edge of a graph.
   346       /// This iterator goes through each edge of a graph.
   347       /// Its usage is quite simple, for example you can count the number
   347       /// Its usage is quite simple, for example you can count the number
   350       /// int count=0;
   350       /// int count=0;
   351       /// for(Graph::EdgeIt e(g); e!=INVALID; ++e) ++count;
   351       /// for(Graph::EdgeIt e(g); e!=INVALID; ++e) ++count;
   352       /// \endcode
   352       /// \endcode
   353       class EdgeIt : public Edge {
   353       class EdgeIt : public Edge {
   354       public:
   354       public:
   355 	/// Default constructor
   355         /// Default constructor
   356 
   356 
   357 	/// @warning The default constructor sets the iterator
   357         /// @warning The default constructor sets the iterator
   358 	/// to an undefined value.
   358         /// to an undefined value.
   359 	EdgeIt() { }
   359         EdgeIt() { }
   360 	/// Copy constructor.
   360         /// Copy constructor.
   361 
   361 
   362 	/// Copy constructor.
   362         /// Copy constructor.
   363 	///
   363         ///
   364 	EdgeIt(const EdgeIt& e) : Edge(e) { }
   364         EdgeIt(const EdgeIt& e) : Edge(e) { }
   365 	/// Initialize the iterator to be invalid.
   365         /// Initialize the iterator to be invalid.
   366 
   366 
   367 	/// Initialize the iterator to be invalid.
   367         /// Initialize the iterator to be invalid.
   368 	///
   368         ///
   369 	EdgeIt(Invalid) { }
   369         EdgeIt(Invalid) { }
   370 	/// This constructor sets the iterator to first edge.
   370         /// This constructor sets the iterator to the first edge.
   371     
   371     
   372 	/// This constructor set the iterator to the first edge of
   372         /// This constructor sets the iterator to the first edge of \c g.
   373 	/// node
   373         ///@param g the graph
   374 	///@param g the graph
   374         EdgeIt(const StaticGraph&) { }
   375 	EdgeIt(const StaticGraph&) { }
   375         /// Edge -> EdgeIt conversion
   376 	/// Edge -> EdgeIt conversion
   376 
   377 
   377         /// Sets the iterator to the value of the trivial iterator \c e.
   378 	/// Sets the iterator to the value of the trivial iterator \c e.
   378         /// This feature necessitates that each time we 
   379 	/// This feature necessitates that each time we 
   379         /// iterate the edge-set, the iteration order is the same.
   380 	/// iterate the edge-set, the iteration order is the same.
   380         EdgeIt(const StaticGraph&, const Edge&) { } 
   381 	EdgeIt(const StaticGraph&, const Edge&) { } 
   381         ///Next edge
   382     	///Next edge
   382         
   383 	
   383         /// Assign the iterator to the next edge.
   384 	/// Assign the iterator to the next 
   384         EdgeIt& operator++() { return *this; }
   385 	/// edge of the corresponding node.
       
   386 	EdgeIt& operator++() { return *this; }
       
   387       };
   385       };
   388       ///Gives back the target node of an edge.
   386       ///Gives back the target node of an edge.
   389 
   387 
   390       ///Gives back the target node of an edge.
   388       ///Gives back the target node of an edge.
   391       ///
   389       ///
   405       template<class T> 
   403       template<class T> 
   406       class NodeMap : public ReadWriteMap< Node, T >
   404       class NodeMap : public ReadWriteMap< Node, T >
   407       {
   405       {
   408       public:
   406       public:
   409 
   407 
   410 	///\e
   408         ///\e
   411 	NodeMap(const StaticGraph&) { }
   409         NodeMap(const StaticGraph&) { }
   412 	///\e
   410         ///\e
   413 	NodeMap(const StaticGraph&, T) { }
   411         NodeMap(const StaticGraph&, T) { }
   414 
   412 
   415 	///Copy constructor
   413         ///Copy constructor
   416 	NodeMap(const NodeMap& nm) : ReadWriteMap< Node, T >(nm) { }
   414         NodeMap(const NodeMap& nm) : ReadWriteMap< Node, T >(nm) { }
   417 	///Assignment operator
   415         ///Assignment operator
   418 	NodeMap& operator=(const NodeMap&) { return *this; }
   416         NodeMap& operator=(const NodeMap&) { return *this; }
   419 	// \todo fix this concept
   417         // \todo fix this concept
   420       };
   418       };
   421 
   419 
   422       /// Read write map of the edges to type \c T.
   420       /// Read write map of the edges to type \c T.
   423 
   421 
   424       /// \ingroup concept
   422       /// \ingroup concept
   429       template<class T> 
   427       template<class T> 
   430       class EdgeMap : public ReadWriteMap<Edge,T>
   428       class EdgeMap : public ReadWriteMap<Edge,T>
   431       {
   429       {
   432       public:
   430       public:
   433 
   431 
   434 	///\e
   432         ///\e
   435 	EdgeMap(const StaticGraph&) { }
   433         EdgeMap(const StaticGraph&) { }
   436 	///\e
   434         ///\e
   437 	EdgeMap(const StaticGraph&, T) { }
   435         EdgeMap(const StaticGraph&, T) { }
   438 	///Copy constructor
   436         ///Copy constructor
   439 	EdgeMap(const EdgeMap& em) : ReadWriteMap<Edge,T>(em) { }
   437         EdgeMap(const EdgeMap& em) : ReadWriteMap<Edge,T>(em) { }
   440 	///Assignment operator
   438         ///Assignment operator
   441 	EdgeMap& operator=(const EdgeMap&) { return *this; }
   439         EdgeMap& operator=(const EdgeMap&) { return *this; }
   442 	// \todo fix this concept    
   440         // \todo fix this concept    
   443       };
   441       };
   444 
   442 
   445       template <typename _Graph>
   443       template <typename _Graph>
   446       struct Constraints : public _StaticGraph::Constraints<_Graph> {};
   444       struct Constraints : public _StaticGraph::Constraints<_Graph> {};
   447 
   445 
   448     };
   446     };
   449 
   447 
   450     /// An empty non-static graph class.
   448     /// An empty non-static graph class.
   451     
   449     
   452     /// This class provides everything that \ref StaticGraph
   450     /// This class provides everything that \ref StaticGraph does.
   453     /// with additional functionality which enables to build a
   451     /// Additionally it enables building graphs from scratch.
   454     /// graph from scratch.
       
   455     class ExtendableGraph : public StaticGraph
   452     class ExtendableGraph : public StaticGraph
   456     {
   453     {
   457     public:
   454     public:
   458       /// Defalult constructor.
   455       /// Defalult constructor.
   459 
   456 
   484 
   481 
   485     };
   482     };
   486 
   483 
   487     /// An empty erasable graph class.
   484     /// An empty erasable graph class.
   488   
   485   
   489     /// This class is an extension of \ref ExtendableGraph. It also makes it
   486     /// This class is an extension of \ref ExtendableGraph. It makes it
   490     /// possible to erase edges or nodes.
   487     /// possible to erase edges or nodes.
   491     class ErasableGraph : public ExtendableGraph
   488     class ErasableGraph : public ExtendableGraph
   492     {
   489     {
   493     public:
   490     public:
   494       /// Defalult constructor.
   491       /// Defalult constructor.