question archive How do I create an copy constructor and the assignment operator? It should add these member functions so that they do the appropriate job of making a deep copy (not shallow copy) of a List object
How do I create an copy constructor and the assignment operator? It should add these member functions so that they do the appropriate job of making a deep copy (not shallow copy) of a List object
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How do I create an copy constructor and the assignment operator? It should add these member functions so that they do the appropriate job of making a deep copy (not shallow copy) of a List object. The assignment operator should work in the same context as with other types. This means cleaning up prior data, protecting against self-assignments, and cascading of calls should work as well.
#include <iostream>
using std::cout;
#include <new>
#include "listnode.h" // ListNode class definition
template< class NODETYPE >
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< NODETYPE > *firstPtr; // pointer to first node
ListNode< NODETYPE > *lastPtr; // pointer to last node
// utility function to allocate new node
ListNode< NODETYPE > *getNewNode( const NODETYPE & );
}; // 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;
// commented out the output -- no need to print what we are deallocating
// cout << tempPtr->data << 'n';
currentPtr = currentPtr->nextPtr;
delete tempPtr;
}
}
// cout << "All nodes destroyednn";
} // end List destructor
// insert node at front of list
template< class NODETYPE >
void List< NODETYPE >::insertAtFront( const NODETYPE &value )
{
ListNode< NODETYPE > *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< class NODETYPE >
void List< NODETYPE >::insertAtBack( const NODETYPE &value )
{
ListNode< NODETYPE > *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< 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
// is List empty?
template< class NODETYPE >
bool List< NODETYPE >::isEmpty() const
{
return firstPtr == 0;
} // end function isEmpty
// return pointer to newly allocated node
template< class NODETYPE >
ListNode< NODETYPE > *List< NODETYPE >::getNewNode(
const NODETYPE &value )
{
return new ListNode< NODETYPE >( value );
} // end function getNewNode
// display contents of List
template< class NODETYPE >
void List< NODETYPE >::print() const
{
if ( isEmpty() ) {
cout << "The list is emptynn";
return;
} // end if
ListNode< NODETYPE > *currentPtr = firstPtr;
cout << "The list is: ";
while ( currentPtr != 0 ) {
cout << currentPtr->data << ' ';
currentPtr = currentPtr->nextPtr;
} // end while
cout << "nn";
} // end function print
