// C++ Program for Implementation of Single linked list
#include <iostream>
using namespace std;
// Structure for a node in the linked list
struct Node
{
int data;
Node* link;
};
Node* head = NULL;
// Function to Insert a new node at the beginning of the list
void insertAtBeginning(int value)
{
Node* newNode = new Node();
newNode->data = value;
newNode->link = head;
head = newNode;
}
// Function Insert a new node at the end of the list
void insertAtEnd(int value)
{
Node* newNode = new Node();
newNode->data = value;
newNode->link = NULL;
// If the list is empty, update the head to the new node
if (head == NULL)
{
head = newNode;
return;
}
// Traverse to the last node
Node* temp = head;
while (temp->link != NULL)
temp = temp->link;
// Update the last node's link to the new node
temp->link = newNode;
}
// Function to Insert a new node at a specific position in the list
void insertAtPosition(int value, int position)
{
if (position < 1) {
cout << "Position should be >= 1." << endl;
return;
}
if (position == 1) {
insertAtBeginning(value);
return;
}
Node* newNode = new Node();
newNode->data = value;
// Traverse to the node before the desired position
Node* temp = head;
for (int i = 1; i < position - 1 && temp !=NULL; ++i)
{
temp = temp->link;
}
// If the position is out of range, print an error message
if (temp ==NULL)
{
cout << "Position out of range." << endl;
delete newNode;
return;
}
// Insert the new node at the desired position
newNode->link = temp->link;
temp->link = newNode;
}
// Function to Delete the first node of the list
void deleteFromBeginning()
{
if (head==NULL)
{
cout << "List is empty." << endl;
return;
}
Node* temp = head;
head = head->link;
delete temp;
}
// Function to Delete the last node of the list
void deleteFromEnd()
{
if (head==NULL)
{
cout << "List is empty." << endl;
return;
}
if (head->link==NULL)
{
delete head;
head = NULL;
return;
}
// Traverse to the second-to-last node
Node* temp = head;
while (temp->link->link)
{
temp = temp->link;
}
// Delete the last node
delete temp->link;
// Set the second-to-last node's link to NULL
temp->link = NULL;
}
// Function to Delete a node at a specific position in the list
void deleteFromPosition(int position)
{
if (position < 1)
{
cout << "Position should be >= 1." << endl;
return;
}
if (position == 1)
{
deleteFromBeginning();
return;
}
Node* temp = head;
for (int i = 1; i < position - 1 && temp !=NULL; ++i)
{
temp = temp->link;
}
if ((temp==NULL) || (temp->link==NULL))
{
cout << "Position out of range." << endl;
return;
}
// Save the node to be deleted
Node* nodeToDelete = temp->link;
// Update the link pointer
temp->link = temp->link->link;
// Delete the node
delete nodeToDelete;
}
// Function to print the nodes value of the linked list
void display()
{
if (head==NULL)
{
cout << "List is empty." << endl;
return;
}
Node* temp = head;
while (temp !=NULL)
{
cout << temp->data << " -> ";
temp = temp->link;
}
cout << "NULL" << endl;
}
int main()
{
int x,p,k;
do
{
cout<<"=================================="<<endl;
cout<<"1) Insert element in the Begining"<<endl;
cout<<"2) Insert element in the End"<<endl;
cout<<"3) Insert element in the Position"<<endl;
cout<<"4) Delete element from the Begining"<<endl;
cout<<"5) Delete element from the End"<<endl;
cout<<"6) Delete element from the Position"<<endl;
cout<<"7) Display elements of the List"<<endl;
cout<<"0) Exit"<<endl;
cout<<"Enter your choice : ";
cin>>k;
switch (k)
{
case 1:{
cout<<"Enter value :";
cin>>x;
insertAtBeginning(x);
cout << "Linked list after insertions: ";
display();
break;
}
case 2:{
cout<<"Enter value :";
cin>>x;
insertAtEnd(x);
cout << "Linked list after insertions: ";
display();
break;
}
case 3:{
cout<<"Enter value :";
cin>>x;
cout<<"Enter position to insert :";
cin>>p;
insertAtPosition(x, p);
cout << "Linked list after insertions: ";
display();
break;
}
case 4:{
deleteFromBeginning();
cout << "Linked list after deleting : ";
display();
break;
}
case 5:{
deleteFromEnd();
cout << "Linked list after deleting : ";
display();
break;
}
case 6:{
cout<<"Enter position to delete :";
cin>>p;
deleteFromPosition(p);
cout << "Linked list after deleting : ";
display();
break;
}
case 7:display();
break;
case 8:cout<<"Exit"<<endl;
break;
default: cout<<"Invalid choice"<<endl;
}
} while( k != 0);
return 0;
}
