Linked Lists Data Structure in C++

Linked Lists
A Linked list is a linear data structure, where the linear order is given by means of pointers. Each element of the linked list is known as nodes.
Each node is divided into two parts:

1. The first part contains the data of the element.
2. The second part contains the address of the next node in the list (next).

Traversing a Linked List in C++

Traversing is the process of displaying all the elements of the linked list. Here, we have traversed the elements of the linked list using functions.

#include <iostream>
using namespace std;
struct node{
    int data;
    struct node*next;
};
void traversal(struct node*ptr);
int main()
{
struct node*head,*second,*third;   
head=new node();
second=new node();
third=new node();

head->data=7;
head->next=second;

second->data=14;
second->next=third;

third->data=21;
third->next=NULL;

node *newnode;
newnode=new node();
traversal(head);
cout<<"n Insert element:";
cin>>newnode->data;
newnode->next=head;
head=newnode; 
traversal(head);
return 0;
}
void traversal(struct node*ptr)
{   while(ptr!=NULL)
    {
        cout<<ptr->data<<" ";
        ptr=ptr->next;
}
}

Algorithm for traversing a Linked List

The variable ptr points to the node currently being processed. The variable head contains the address of the head node of the LIST.
void traversal(struct node*ptr)
1.ptr=head (Initialize pointers)
2. Repeat steps 3 and 4 while PTR!= NULL
3. Apply the PROCESS to data[PTR].
4. Set ptr=next[PTR]5. Exit

Insertion in a Linked List in C++

Output:
Enter data:56
Do you want to insert another number? (y/n)y
Enter data:23
Do you want to insert another number? (y/n)y
Enter data:96
Do you want to insert another number? (y/n)n
Elements in Linked list: 56 23 96

#include<iostream>
using namespace std;
struct node{
int data;
node*next;
};
int main()
{
char ch;
node *head,*newnode,*temp;
head = NULL;
do
{
newnode=new node();
cout<<"n Enter data:";
cin>>newnode->data;
newnode->next=NULL;
if(head==NULL)
head=temp=newnode;
else
{
temp->next=newnode;
temp=newnode;
}
cout<<"n Do you want to insert another number? (y/n)";
cin>>ch;
}while(ch=='y');
temp=head;
cout<<"n Elements in Linked list: ";
while(temp!=NULL)
{
cout<<temp->data<<" ";
temp=temp->next;
}
return 0;
}

#include <iostream>
using namespace std;
struct node{
    int data;
    struct node*next;
};
void traversal(struct node*ptr);
int main()
{
struct node*head,*second,*third;
head=new node();
second=new node();
third=new node();

head->data=7;
head->next=second;

second->data=14;
second->next=third;

third->data=21;
third->next=NULL;

cout<<”n Elements of linked list:”;
traversal(head);

cout<<"n After Deletionn";
cout<<”n Elements of linked list:”;
struct node*temp;
    temp=head;
    head=head->next;
    free(temp);

traversal(head);
return 0;
}
void traversal(struct node*ptr)
{   while(ptr!=NULL)
    {

        cout<<ptr->data<<" ";
        ptr=ptr->next;
}
}