// Fig. 21.3: listnode.h // Template ListNode class definition. #ifndef LISTNODE_H #define LISTNODE_H // forward declaration of class List template class List; template class ListNode { friend class List; // make List a friend public: ListNode( const NODETYPE & ); // constructor NODETYPE getData() const; // return data in node private: NODETYPE data; // data ListNode *nextPtr; // next node in list }; // end class ListNode // constructor template ListNode::ListNode( const NODETYPE &info ) : data( info ), nextPtr( 0 ) { // empty body } // end ListNode constructor // return copy of data in node template NODETYPE ListNode::getData() const { return data; } // end function getData #endif

************************************************************************************************************

#ifndef LIST_H #define LIST_H #include using std::cout; #include #include "listnode.h" // ListNode class definition template class List { public: List(); // constructor ~List(); // destructor void insertAtFront( const NODETYPE & ); void insertAtBack( const NODETYPE & ); bool removeFromFront( NODETYPE & ); bool removeFromBack( NODETYPE & ); bool isEmpty() const; void print() const; private: ListNode *firstPtr; // pointer to first node ListNode *lastPtr; // pointer to last node // utility function to allocate new node ListNode *getNewNode( const NODETYPE & ); }; // end class List // default constructor template List::List() : firstPtr( 0 ), lastPtr( 0 ) { // empty body } // end List constructor // destructor template List::~List() { if ( !isEmpty() ) { // List is not empty // cout  *currentPtr = firstPtr; ListNode *tempPtr; while ( currentPtr != 0 ) // delete remaining nodes { tempPtr = currentPtr; // commented out the output -- no need to print what we are deallocating // cout data nextPtr; delete tempPtr; } } // cout  void List::insertAtFront( const NODETYPE &value ) { ListNode *newPtr = getNewNode( value ); if ( isEmpty() ) // List is empty firstPtr = lastPtr = newPtr; else { // List is not empty newPtr->nextPtr = firstPtr; firstPtr = newPtr; } // end else } // end function insertAtFront // insert node at back of list template void List::insertAtBack( const NODETYPE &value ) { ListNode *newPtr = getNewNode( value ); if ( isEmpty() ) // List is empty firstPtr = lastPtr = newPtr; else { // List is not empty lastPtr->nextPtr = newPtr; lastPtr = newPtr; } // end else } // end function insertAtBack // delete node from front of list template bool List::removeFromFront( NODETYPE &value ) { if ( isEmpty() ) // List is empty return false; // delete unsuccessful else { ListNode *tempPtr = firstPtr; if ( firstPtr == lastPtr ) firstPtr = lastPtr = 0; else firstPtr = firstPtr->nextPtr; value = tempPtr->data; // data being removed delete tempPtr; return true; // delete successful } // end else } // end function removeFromFront // delete node from back of list template bool List::removeFromBack( NODETYPE &value ) { if ( isEmpty() ) return false; // delete unsuccessful else { ListNode *tempPtr = lastPtr; if ( firstPtr == lastPtr ) firstPtr = lastPtr = 0; else { ListNode *currentPtr = firstPtr; // locate second-to-last element while ( currentPtr->nextPtr != lastPtr ) currentPtr = currentPtr->nextPtr; lastPtr = currentPtr; currentPtr->nextPtr = 0; } // end else value = tempPtr->data; delete tempPtr; return true; // delete successful } // end else } // end function removeFromBack // is List empty? template bool List::isEmpty() const { return firstPtr == 0; } // end function isEmpty // return pointer to newly allocated node template ListNode *List::getNewNode( const NODETYPE &value ) { return new ListNode( value ); } // end function getNewNode // display contents of List template void List::print() const { if ( isEmpty() ) { cout  *currentPtr = firstPtr; cout data nextPtr; } // end while cout  
 *******************************************************************************************************
 
// Test program for HW 7 // #include using std::cin; using std::endl; #include using std::string; #include "list.h" // List class definition void instructions(); // function to test a List template void testList( List &listObject, const string &typeName ) { cout > choice; switch ( choice ) { case 1: cout > value; listObject.insertAtFront( value ); listObject.print(); break; case 2: cout > value; listObject.insertAtBack( value ); listObject.print(); break; case 3: cout > value; cout > pos; listObject.insertMiddle( value , pos ); listObject.print(); break; case 4: if ( listObject.removeFromFront( value ) ) cout > pos; if ( listObject.removeMiddle( value, pos ) ) cout  integerList; testList( integerList, "integer" ); // test List of double values List doubleList; testList( doubleList, "double" ); return 0; } // end main 
 
 ***********************************************************************************************************************