C++ Linked List Exercises: Delete first node of a Singly Linked List

Last update on December 20 2024 12:23:46 (UTC/GMT +8 hours)

Write a C++ program to delete first node of a given Singly Linked List.

Test Data:
Original Linked list:
13 11 9 7 5 3 1
Delete first node of Singly Linked List:
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 a structure for defining a Node
struct Node {
    int num; // Data field to store a number
    Node *next; // Pointer to the next node
};

struct Node *head = NULL; // Starting (Head) node initialized as NULL

// Function to insert a node at the start of the linked list
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 delete the first node of the list
void delete_first_node() {
    if (head != NULL) { // Check if the list is not empty
        Node* temp = head; // Temporary pointer to the current head
        head = head->next; // Move the head to the next node
        free(temp); // Free the memory of the original head node
    }
}

// Function to display all nodes in the linked list
void display_all_nodes() {
    struct Node *temp = head; // Temporary pointer to traverse the list
    while (temp != NULL) { // Loop through all nodes until the end is reached
        cout << temp->num << " "; // Displaying the data in the current node
        temp = temp->next; // Move 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"; // Displaying message for the original list
    display_all_nodes(); // Displaying all nodes in the original list

    cout << "\n\nDelete first node of Singly Linked List:\n"; // Displaying message for the deletion
    delete_first_node(); // Deleting the first node of the list
    display_all_nodes(); // Displaying all nodes after deletion

    cout << endl; // Displaying newline
    return 0; // Returning from the main function
}

Sample Output:

Original Linked list:
13 11 9 7 5 3 1 

Delete first node of  Singly Linked List:
11 9 7 5 3 1 

Flowchart:

CPP Code Editor:

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Previous C++ Exercise: Insert a node at any position of a Singly Linked List.
Next C++ Exercise: Delete a middle node from a Singly Linked List.