C++ Linked List Exercises: Insert a new node at the beginning of a Linked List

Last update on December 20 2024 12:30:13 (UTC/GMT +8 hours)

Write a C++ program to insert a new node at the beginning of a Singly Linked List.

Visualization:

Test Data:
Original Linked list:
13 11 9 7 5 3 1
Insert a new node at the beginning of a Singly Linked List:
0 13 11 9 7 5 3 1

Sample Solution:

C++ Code:

#include <iostream> // Including input-output stream header file

using namespace std; // Using standard namespace

//Declare node 
struct Node{
    int num; // Data field to store a number
    Node *next; // Pointer to the next node
};

//Starting (Head) node
struct Node *head=NULL; // Initializing the head node as NULL initially

//Insert node at start
void insert_Node(int n){
    struct Node *new_node=new Node; // Creating a new node
    new_node->num=n; // Assigning data to the new node
    new_node->next=head; // Pointing the new node to the current head
    head=new_node; // Making the new node as the head
}

// Function to insert a new node at the beginning of the linked list
void NodeInsertatBegin(int new_element) {
    // Create a new node
    Node* new_Node = new Node();
    new_Node->num = new_element; // Assigning data to the new node
    new_Node->next = head; // Pointing the new node to the current head
    head = new_Node; // Making the new node as the head
}

//Display all nodes
void display_all_nodes() {
    struct Node *temp = head; // Temporary node to traverse the list
    while(temp != NULL) { // Loop to iterate through the list
        cout << temp->num << " "; // Displaying the data in the current node
        temp = temp->next; // Moving to the next node
    }
}

int main(){
    insert_Node(1); // Inserting a node with value 1
    insert_Node(3); // Inserting a node with value 3
    insert_Node(5); // Inserting a node with value 5
    insert_Node(7); // Inserting a node with value 7
    insert_Node(9); // Inserting a node with value 9
    insert_Node(11); // Inserting a node with value 11
    insert_Node(13); // Inserting a node with value 13

    cout << "Original Linked list:\n";
	display_all_nodes(); // Displaying all nodes in the original list

	cout << "\n\nInsert a new node at the beginning of a Singly Linked List:\n";
    NodeInsertatBegin(0); // Inserting a new node with value 0 at the beginning
    display_all_nodes(); // Displaying all nodes after insertion
    cout << endl; // Displaying newline

    return 0; // Returning from the main function
}

Sample Output:

Original Linked list:
13 11 9 7 5 3 1 

Insert a new node at the beginning of a Singly Linked List:
0 13 11 9 7 5 3 1 

Flowchart:

CPP Code Editor:

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