Insert a node at last nth position of linked list in c

C program for insert node in nth last position in linked list. Here Problem description and explanation.

/*
    C program for
    Linked list insert node at last nth position
*/
#include <stdio.h>
#include <stdlib.h>

// Linked List LinkNode
struct LinkNode
{
    int data;
    struct LinkNode * next;
};
// Singly linked list 
struct SingleLL
{
    struct LinkNode * head;
};
// Returns the new linked list
struct SingleLL * newLinkedList()
{
    // Create memory of head and tail Nodes
    struct SingleLL * sll = (struct SingleLL * )
    malloc(sizeof(struct SingleLL));
    if (sll == NULL)
    {
        printf("Memory overflow\n");
    }
    else
    {
        sll->head = NULL;
    }
    return sll;
}
// Returns a new linked list node
struct LinkNode * newLinkedNode(int data)
{
    struct LinkNode * node = (struct LinkNode * )
    malloc(sizeof(struct LinkNode));
    if (node == NULL)
    {
        printf("Memory overflow to create node\n");
    }
    else
    {
        // Set node values
        node->data = data;
        node->next = NULL;
    }
    return node;
}
// Display linked list element
void display(struct LinkNode * node)
{
    if (node == NULL)
    {
        return;
    }
    struct LinkNode * temp = node;
    // iterating linked list elements
    while (temp != NULL)
    {
        printf(" %d →", temp->data);
        // Visit to next node
        temp = temp->next;
    }
    printf(" NULL\n");
}
// Handles the request of adding new node at end of linked list
void addNode(struct SingleLL * sll, int data)
{
    // Create dynamic node
    struct LinkNode * node = newLinkedNode(data);
    if (node == NULL)
    {
        // Handle memory overflow 
        printf("Memory overflow to Create LinkNode\n");
        return;
    }
    if (sll->head == NULL)
    {
        // First node in linked list
        sll->head = node;
    }
    else
    {
        struct LinkNode * temp = sll->head;
        // Find the last node
        while (temp != NULL && temp->next != NULL)
        {
            temp = temp->next;
        }
        // Add node at last position
        temp->next = node;
    }
}
// Add node at the last nth possition
void add_nth_last(struct SingleLL * sll, int nth, int value)
{
    if (sll->head == NULL)
    {
        printf("\nEmpty Linked List");
    }
    else if (nth <= 0)
    {
        printf("\nPlease give of a valid node position");
    }
    else
    {
        struct LinkNode * temp = sll->head;
        struct LinkNode * location = NULL;
        while (temp != NULL)
        {
            nth--;
            if (nth <= 0)
            {
                if (location == NULL)
                {
                    location = sll->head;
                }
                else
                {
                    location = location->next;
                }
            }
            temp = temp->next;
        }
        if (nth > 1)
        {
            // When not possible to add node
            printf("\nInvalid position");
        }
        else
        {
            // Create new node
            struct LinkNode * node = newLinkedNode(value);
            if (node != NULL)
            {
                if (location == NULL)
                {
                    // insert node at begining
                    node->next = sll->head;
                    sll->head = node;
                }
                else
                {
                    node->next = location->next;
                    location->next = node;
                }
                // Display all node
                display(sll->head);
            }
        }
    }
}
int main(int argc, char
    const * argv[])
{
    struct SingleLL * sll = newLinkedList();
    // Linked list
    // 5 → 4 → 3 → 2 → 1 → NULL
    addNode(sll, 5);
    addNode(sll, 4);
    addNode(sll, 3);
    addNode(sll, 2);
    addNode(sll, 1);
    printf("Before Linked List node : \n");
    display(sll->head);
    // Assume that position is positive integer
    int nth = 2, data = 10;
    printf("After insert node at %d last position : \n", nth);
    add_nth_last(sll, nth, data);
    return 0;
}
Before Linked List node :
 5 → 4 → 3 → 2 → 1 → NULL
After insert node at 2 last position :
 5 → 4 → 3 → 2 → 10 → 1 → NULL


Please share your knowledge to improve code and content standard. Also submit your doubts, and test case. We improve by your feedback. We will try to resolve your query as soon as possible.

New Comment







© 2021, kalkicode.com, All rights reserved