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#include "LinkedList.h"
//*****************************************************************
// appendNode appends a node containing the value passed into *
// newValue, to the end of the list. *
//*****************************************************************
void LinkedList::appendNode(int num)
{
ListNode *newNode;
ListNode *nodePtr;
// Allocate a new node and store num there.
newNode = new ListNode;
newNode -> value = num;
newNode -> next = NULL;
// If there are no nodes in the list,
// make newNode the first node.
if(!head)
head = newNode;
else
{
// Initialize nodePtr to head of list.
nodePtr = head;
// Find the last node in the list.
while(nodePtr -> next)
nodePtr = nodePtr -> next;
// Insert newNode as the last node.
nodePtr -> next = newNode;
}
Display();
}
//*****************************************************************
// Display shows the value stored in each node of the linked list *
// pointed to by the head. *
//*****************************************************************
void LinkedList::Display() const
{
ListNode *nodePtr;
if(!head)
{
cout << "\n\tThe list is empty.";
return;
}
// Position nodePtr at the head of list.
nodePtr = head;
cout << "\n\n\tThe elements in this list are: \n\t";
// While nodePtr points to a node, traverse
// the list.
while(nodePtr)
{
cout << nodePtr -> value << " -> ";
nodePtr = nodePtr -> next;
}
// End of the chain.
cout << "NULL";
}
//*****************************************************************
// insertNode function inserts a node with newValue copied to its *
// value member. *
//*****************************************************************
void LinkedList::insertNode(int num)
{
ListNode *newNode;
ListNode *nodePtr;
ListNode *previousNode = NULL;
// Allocate a new node and store num there.
newNode = new ListNode;
newNode -> value = num;
newNode -> next = NULL;
// If there are no nodes in the list,
// make newNode the first node.
if(!head)
head = newNode;
else
{
nodePtr = head;
previousNode = NULL;
// Skip all nodes whose value is less than num.
while(nodePtr != NULL && nodePtr -> value < num)
{
previousNode = nodePtr;
nodePtr = nodePtr -> next;
}
// If newNode is to be the first in the list,
// insert it before all other nodes.
if(previousNode == NULL)
{
head = newNode;
newNode -> next = nodePtr;
}
else
{
previousNode -> next = newNode;
newNode -> next = nodePtr;
}
}
// Display results.
Display();
}
//*****************************************************************
// Reverse function will re-arrange the nodes in the list. *
//*****************************************************************
void LinkedList::Reverse()
{
ListNode *nodePtr;
ListNode *next;
ListNode *result = NULL;
// If the list is empty, display
// message and do nothing.
if(!head)
{
cout << "\n\tThe list is empty.";
return;
}
// Initialize nodePtr to the head of the list.
nodePtr = head;
// While nodePtr is not at the end of the list...
while(nodePtr != NULL)
{
next = nodePtr -> next;
nodePtr -> next = result;
result = nodePtr;
nodePtr = next;
}
// Position result at the head of the list.
head = result;
// Display results.
Display();
}
//*****************************************************************
// The deleteNode function searches for a node with num as its *
// value. The node, if found, is deleted from the list and from *
// memory. *
//*****************************************************************
void LinkedList::deleteNode(int num)
{
ListNode *nodePtr;
ListNode *previousNode;
// If the list is empty, display
// message and do nothing.
if(!head)
{
cout << "\n\tFailed to delete. List is empty.";
return;
}
// Determine if the first node is the one.
if(head -> value == num)
{
nodePtr = head -> next;
delete head;
head = nodePtr;
}
else
{
// Initialize nodePtr to the head of the list.
nodePtr = head;
// Skip all nodes whose value member is not
// equal to num.
while(nodePtr != NULL && nodePtr -> value != num)
{
previousNode = nodePtr;
nodePtr = nodePtr -> next;
}
// If nodePtr is not at the end of the list,
// link the previous node to the node after
// nodePtr, then delete nodePtr.
if(nodePtr)
{
previousNode -> next = nodePtr -> next;
delete nodePtr;
}
else
cout << "\n\tFailed to delete as " << num
<< " because it is not found in the list.";
}
// Display results.
Display();
}
//*****************************************************************
// Function Search searches for a value and returns the position *
// if found. If its not found, -1 is then returned. *
//*****************************************************************
int LinkedList::Search(int value)
{
ListNode *nodePtr;
int pos = -1;
int location = -1;
bool found = false;
// If the list is empty, display
// message and do nothing.
if(!head)
{
cout << "\n\tThe list is empty.\n";
//return -1;
location = -1;
found = true;
}
// Initialize nodePtr to the head of the list.
nodePtr = head;
// While nodePtr points to a node, traverse
// the list.
while(nodePtr && !found)
{
pos++; // Increment position.
// Determine if the first node is the one.
if(nodePtr -> value == value)
{
location = pos;
found = true;
}
else
nodePtr = nodePtr -> next;
}
// Return -1.
return -1;
}
//*****************************************************************
// Destructor. *
// This function deletes every node in the list. *
//*****************************************************************
LinkedList::~LinkedList()
{
ListNode *nodePtr;
ListNode *nextNode;
// Position nodePtr at the head of the list.
nodePtr = head;
// While nodePtr is not at the end of the list...
while(nodePtr != NULL)
{
nextNode = nodePtr -> next;
delete nodePtr;
nodePtr = nextNode;
}
}
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