Linked List Types

1. Singly Linked List
2. Doubly Linked List
3. Circular Linked List
4. Node Insertion
5. Node Deletion

Code Implemantation

1. Node and List Structure

typedef struct ListNode {
    int value;
    struct ListNode* next;
} ListNode;

typedef struct LinkedList {
    ListNode* first;
    size_t count;
} LinkedList;

2. List Initialization

void initList(LinkedList* lst) {
    lst->first = NULL;
    lst->count = 0;
}

3. List Destruciton

void destroyList(LinkedList* lst) {
    ListNode* current = lst->first;
    while (current) {
        ListNode* temp = current;
        current = current->next;
        free(temp);
    }
    lst->first = NULL;
    lst->count = 0;
}

4. Node Insertion

void insertNode(LinkedList* lst, int pos, int val) {
    if (pos < 0 || pos > lst->count) {
        printf("Invalid position\n");
        return;
    }
    
    ListNode* newNode = (ListNode*)malloc(sizeof(ListNode));
    newNode->value = val;
    
    if (pos == 0) {
        newNode->next = lst->first;
        lst->first = newNode;
    } else {
        ListNode* prev = lst->first;
        for (int i = 0; i < pos - 1; i++) {
            prev = prev->next;
        }
        newNode->next = prev->next;
        prev->next = newNode;
    }
    lst->count++;
}

5. Node Deletion

void removeNode(LinkedList* lst, int pos) {
    if (pos < 0 || pos >= lst->count) {
        printf("Invalid position\n");
        return;
    }
    
    if (pos == 0) {
        ListNode* temp = lst->first;
        lst->first = lst->first->next;
        free(temp);
    } else {
        ListNode* prev = lst->first;
        for (int i = 0; i < pos - 1; i++) {
            prev = prev->next;
        }
        ListNode* toDelete = prev->next;
        prev->next = toDelete->next;
        free(toDelete);
    }
    lst->count--;
}

6. Node Search

ListNode* findNode(LinkedList* lst, int val) {
    ListNode* current = lst->first;
    while (current) {
        if (current->value == val) {
            return current;
        }
        current = current->next;
    }
    return NULL;
}

7. Get Node by Position

ListNode* getNodeAt(LinkedList* lst, int pos) {
    if (pos < 0 || pos >= lst->count) {
        printf("Invalid position\n");
        return NULL;
    }
    
    ListNode* current = lst->first;
    for (int i = 0; i < pos; i++) {
        current = current->next;
    }
    return current;
}

8. Modify Node Value

void updateNode(LinkedList* lst, int pos, int val) {
    ListNode* target = getNodeAt(lst, pos);
    if (target) {
        target->value = val;
    }
}

9. Print List

void printList(LinkedList* lst) {
    ListNode* current = lst->first;
    while (current) {
        printf("%d ", current->value);
        current = current->next;
    }
    printf("NULL\n");
}

10. Compleet Example

#include <stdio.h>
#include <stdlib.h>

int main() {
    LinkedList myList;
    initList(&myList);
    
    insertNode(&myList, 0, 5);
    insertNode(&myList, 1, 15);
    insertNode(&myList, 2, 25);
    
    printf("Initial list: ");
    printList(&myList);
    
    removeNode(&myList, 1);
    updateNode(&myList, 0, 10);
    
    printf("Modified list: ");
    printList(&myList);
    
    destroyList(&myList);
    return 0;
}