Insertion Oprations in Linked List

Insertion at the beginning

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To insert the node at the beginning we need to create a new node and assign the head to the new node and the new node to the head.

Code

insertion.cpp

#include <iostream>
using namespace std;
 
class Node {
    public:
    int data;
    Node* next;
 
    Node(int data) {
        this->data = data;
        this->next = nullptr;
    }
};
 
void insertAtBeginning(Node* &head, int data) {
    Node* newNode = new Node(data);
    newNode->next = head;
    head = newNode;
}
 
void printList(Node* head) {
    Node* temp = head;
    while(temp != nullptr) {
        cout << temp->data << "->";
        temp = temp->next;
    }
    cout<<"NULL\n";
}
 
int main() {
    Node*head = new Node(19);
    insertAtBeginning(head, 10);
    return 0;
}

Output

10->19->NULL

Explanation

The line number 15 - 16 is function which insert the node at the beginning of the linked List.
This creates a new node with the data passed and assigns the head to the next of the new node.

Insertion at the tail

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Introduction Patterns