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// Template List class definition
#ifndef LIST_H
#define LIST_H
#include <iostream>
using std::cout;
#include <new>
#include "listnode.h" // ListNode class definition
template< class NODETYPE >
class List {
public:
List();
~List();
void insertInOrder( const NODETYPE &value );
bool removeFromFront( NODETYPE & );
bool removeFromBack( NODETYPE & );
bool deleteNode( const NODETYPE &, NODETYPE & );
bool isEmpty() const;
void print() const;
private:
void insertAtFront( const NODETYPE & );
void insertAtBack( const NODETYPE & );
ListNode< NODETYPE > *firstPtr; // pointer to first node
ListNode< NODETYPE > *lastPtr; // pointer to last node
}; // end class List
// default constructor
template< class NODETYPE >
List< NODETYPE >::List()
: firstPtr( 0 ),
lastPtr( 0 )
{
// empty body
} // end List constructor
// destructor
template< class NODETYPE >
List< NODETYPE >::~List()
{
if ( !isEmpty() ) { // List is not empty
cout << "Destroying nodes ...\n";
ListNode< NODETYPE > *currentPtr = firstPtr;
ListNode< NODETYPE > *tempPtr;
while ( currentPtr != 0 ) { // delete remaining nodes
tempPtr = currentPtr;
cout << tempPtr->data << '\n';
currentPtr = currentPtr->nextPtr;
delete tempPtr;
} // end while
} // end if
cout << "All nodes destroyed\n\n";
} // end List destructor
// insert node at front of list
template< class NODETYPE >
void List< NODETYPE >::insertAtFront( const NODETYPE &value )
{
ListNode< NODETYPE > *newPtr = new ListNode< NODETYPE >( 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< class NODETYPE >
void List< NODETYPE >::insertAtBack( const NODETYPE &value )
{
ListNode< NODETYPE > *newPtr = new ListNode< NODETYPE >( 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< class NODETYPE >
bool List< NODETYPE >::removeFromFront( NODETYPE &value )
{
if ( isEmpty() ) // List is empty
return false; // delete unsuccessful
else {
ListNode< NODETYPE > *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< class NODETYPE >
bool List< NODETYPE >::removeFromBack( NODETYPE &value )
{
if ( isEmpty() )
return false; // delete unsuccessful
else {
ListNode< NODETYPE > *tempPtr = lastPtr;
if ( firstPtr == lastPtr )
firstPtr = lastPtr = 0;
else {
ListNode< NODETYPE > *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
// insert node in sorted order
template< class NODETYPE >
void List< NODETYPE >::insertInOrder( const NODETYPE &value )
{
if ( isEmpty() ) {
ListNode< NODETYPE > *newPtr = new ListNode< NODETYPE >( value );
firstPtr = lastPtr = newPtr;
}
else {
if( firstPtr->data >= value)
insertAtFront( value );
else if( lastPtr->data < value)
insertAtBack( value );
else {
ListNode< NODETYPE > *currentPtr = firstPtr->nextPtr,
*previousPtr = firstPtr,
*newPtr = new ListNode< NODETYPE >( value );
// locate element before new node gets inserted
while ( currentPtr != lastPtr && currentPtr->data < value ) {
previousPtr = currentPtr;
currentPtr = currentPtr->nextPtr;
}
previousPtr->nextPtr = newPtr;
newPtr->nextPtr = currentPtr;
} // end else
} // end else
} // end function insertInOrder
// delete a node from anywhere in the list
template< class NODETYPE >
bool List< NODETYPE >::deleteNode( const NODETYPE &value, NODETYPE &deletedVal )
{
if ( isEmpty() )
return false; // delete unsuccessful
else {
if ( firstPtr->data == value ) {
removeFromFront( deletedVal );
return true; // delete successful
}
else if ( lastPtr->data == value ) {
removeFromBack( deletedVal );
return true; // delete successful
}
else {
ListNode< NODETYPE > *currentPtr = firstPtr->nextPtr,
*previousPtr = firstPtr;
while ( currentPtr != lastPtr && currentPtr->data < value ) {
previousPtr = currentPtr;
currentPtr = currentPtr->nextPtr;
}
if ( currentPtr->data == value ) {
ListNode< NODETYPE > *tempPtr = currentPtr;
deletedVal = currentPtr->data;
previousPtr = currentPtr->nextPtr;
delete tempPtr;
return true; // delete successful
}
else
return false; // delete unsuccessful
} // end else
} // end else
} // end function deleteNode
// is List empty?
template< class NODETYPE >
bool List< NODETYPE >::isEmpty() const
{
return firstPtr == 0;
} // end function isEmpty
// display contents of List
template< class NODETYPE >
void List< NODETYPE >::print() const
{
if ( isEmpty() ) {
cout << "The list is empty\n\n";
return;
} // end if
ListNode< NODETYPE > *currentPtr = firstPtr;
cout << "The list is: ";
while ( currentPtr != 0 ) {
cout << currentPtr->data << ' ';
currentPtr = currentPtr->nextPtr;
} // end while
cout << "\n\n";
} // end function print
#endif
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