C++ Program to Perform Searching Using Self-Organizing Lists

Code:

#include   iostream

using namespace std;

// A structure to representing a node.
struct node
{
int data;
node *next;
};

// A function to create a new node.
node* CreateNode(int data)
{
node *newnode = new node;
newnode->data = data;
newnode->next = NULL;
return newnode;
}

// A function to add the data at the end of the list.
node* InsertIntoList(node *head, int data)
{
node *temp = CreateNode(data);
node *t = new node;
t = head;
if(head == NULL)
{
head = temp;
return head;
}
else
{
// Traversing to the end of the list.
while(t->next != NULL)
t = t->next;
// Add the node at the end. 
t->next = temp;
}
return head;
}

void Display(node *head)
{
node *temp = new node;
temp = head;
cout<<"\n The list state is :";
// Display the list.
while(temp->next != NULL)
{
cout<<"->"<data;
temp = temp->next;
}
}

node* SearchItem(node *head, int item)
{
int flag = 0;
node *temp = new node;
node *t = new node;
temp = head;
if(temp->data == item)
{
cout<<"\nItem found at head node";
flag = 5;
Display(head);
return head;
}
else
{
while((temp->next)->next != NULL)
{
if((temp->next)->data == item)
{
cout<<"\n item found";
flag = 5;
break;
}
temp = temp->next;
}
// Organising the list.
// Shifting the searched node to the head.
t = (temp->next)->next;
(temp->next)->next = head;
head = temp->next;
temp->next = t;
if(flag == 5)
Display(head);
else
cout<<"\nItem not found.";
}
return head;
}

int main()
{
int i, n;
char ch;
node *head = new node;
head = NULL;

for(i = 1; i < 11; i++)
head = InsertIntoList(head, i);

Display(head);

up:
cout<<"\nEnter the Element to be searched: ";
cin>>n;
// Update the head of the list.
head = SearchItem(head, n);

cout<<"\n\n\tDo you want to search more...enter choice(y/n)?";
cin>>ch;
if(ch == 'y' || ch == 'Y')
goto up;

return 0;
}


Output:

Case 1:
 The list state is :->1->2->3->4->5->6->7->8->9
Enter the Element to be searched: 9
item found

The list state is :->9->1->2->3->4->5->6->7->8
Do you want to search more...enter choice(y/n)?y

Enter the Element to be searched: 6
item found

The list state is :->6->9->1->2->3->4->5->7->8
Do you want to search more...enter choice(y/n)?n



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