// this file presents a definition to the template clss Listnode #ifndef TEMLISTNODE_H#define TEMLISTNODE_H#include <iostream.h>template <class Nodetype> class List;template < class Nodetype> class Listnode {friend class List<Nodetype>;public:   Listnode( Nodetype ,  Listnode <Nodetype> *);   ~Listnode();   Listnode <Nodetype> *getnext (){return nextptr;};   void set_sup (int sp){support = sp;};   void set_comblnth (int cm){combl = cm;};   int com(){return combl;};   int sup() {return support;};   int comblnth() {return combl;};   void set_next(Listnode *next){nextptr = next;};   void set_data(Nodetype value){data = value;};   Nodetype getdata() {return data;};   void clear();private:   Nodetype data;   Listnode <Nodetype> *nextptr;   int support;   int combl;};// constructor template <class Nodetype> Listnode <Nodetype>::Listnode(Nodetype info, Listnode<Nodetype> *next){  data = info;  nextptr = next;  support=0;  combl=0;} //destructortemplate <class Nodetype> Listnode <Nodetype>::~Listnode() {  nextptr = NULL;  data = 0;  support = 0;  combl = 0;}template <class Nodetype> void Listnode<Nodetype>::clear(){   nextptr = NULL;   data = 0;   support = 0;   combl = 0;} #endif