C++ Linked List Exercises: Get N^th node in a Singly Linked List

C++ Linked List: Exercise-8 with Solution

Write a C++ program to get N^th node in a given Singly Linked List.

Test Data:
Original list:
7 5 3 1
Position: 1
Value: 7
Position: 2
Value: 5
Position: 3
Value: 3
Position: 4
Value: 1

Sample Solution:

C++ Code:

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

using namespace std; // Using standard namespace

// Structure for defining a Node
struct Node {
    int num; // Data field to store a number
    Node *next; // Pointer to the next node
}; // Node constructed

int sz = 0; // Initializing variable to keep track of the size of the linked list

// Function to insert a node at the beginning of the linked list
void insert(Node** head, int num) {
    Node* new_Node = new Node(); // Creating a new node
    new_Node->num = num; // 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
    sz++; // Increasing the size of the linked list
}

// Function to get the value of the node at a specific position in the linked list
int get_Nth_Node(Node *head, int value) {
    Node *current_Pointer = head; // Pointer to traverse the list
    int length = 0; // Initializing length to zero

    while (current_Pointer != NULL) { // Loop through the list until the end is reached
        if (length == value) // If the position matches the desired value
            return (current_Pointer->num); // Return the value of the node at that position
        length++; // Incrementing the length
        current_Pointer = current_Pointer->next; // Moving to the next node
    }
    return -1; // If the position is not found, return -1
}

// Display all nodes in the linked list
void display_all_nodes(Node* node) {
    while (node != NULL) {
        cout << node->num << " "; // Displaying the data in the current node
        node = node->next; // Move to the next node
    } 
}

int main() {
    Node* head = NULL; // Initializing the head of the linked list as NULL

    insert(&head, 1); // Inserting a node with value 1
    insert(&head, 3); // Inserting a node with value 3
    insert(&head, 5); // Inserting a node with value 5
    insert(&head, 7); // Inserting a node with value 7

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

    int pos = 1;
    cout << "\n\nPosition: " << pos; // Displaying the position
    int result = get_Nth_Node(head, pos - 1); // Getting the value at the specified position
    cout << "\nValue: " << result; // Displaying the value

    pos = 2;
    cout << "\n\nPosition: " << pos; // Displaying the position
    result = get_Nth_Node(head, pos - 1); // Getting the value at the specified position
    cout << "\nValue: " << result; // Displaying the value

    pos = 3;
    cout << "\n\nPosition: " << pos; // Displaying the position
    result = get_Nth_Node(head, pos - 1); // Getting the value at the specified position
    cout << "\nValue: " << result; // Displaying the value

    pos = 4;
    cout << "\n\nPosition: " << pos; // Displaying the position
    result = get_Nth_Node(head, pos - 1); // Getting the value at the specified position
    cout << "\nValue: " << result; // Displaying the value

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

Sample Output:

Original list:
7 5 3 1

Position: 1
Value: 7

Position: 2
Value: 5

Position: 3
Value: 3

Position: 4
Value: 1

Flowchart:

CPP Code Editor:

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