C Linked Lists

C linked lists

Created By: chatGPT

Linked lists are a fundamental data structure in C that enable dynamic memory allocation and efficient insertion and deletion of elements. Unlike arrays, linked lists do not have a fixed size, allowing them to grow and shrink as necessary. A linked list is composed of nodes, where each node contains data and a pointer to the next node in the sequence.

struct Node {
    int data;
    struct Node* next;
};

To create a new node, you need to allocate memory for it and set its data and next pointer. This is typically done using the malloc function from the stdlib.h library, which allocates a block of memory.

struct Node* createNode(int data) {
    struct Node* newNode = (struct Node*)malloc(sizeof(struct Node));
    if (!newNode) {
        printf("Memory allocation failed");
        exit(1);
    }
    newNode->data = data;
    newNode->next = NULL;
    return newNode;
}

In a linked list, you need to keep track of the head of the list, which serves as the entry point for accessing the nodes. When you want to add a node, you can either insert it at the beginning, end, or at a specific position in the list.

void insertAtBeginning(struct Node** head, int data) {
    struct Node* newNode = createNode(data);
    newNode->next = *head;
    *head = newNode;
}

To insert a node at the end of the linked list, you must traverse the list until you reach the last node, then link the new node to the end.

void insertAtEnd(struct Node** head, int data) {
    struct Node* newNode = createNode(data);
    if (*head == NULL) {
        *head = newNode;
        return;
    }
    struct Node* last = *head;
    while (last->next != NULL) {
        last = last->next;
    }
    last->next = newNode;
}

When dealing with linked lists, it's important to implement a function to free the allocated memory. This helps to prevent memory leaks in your program.

void freeList(struct Node* head) {
    struct Node* temp;
    while (head != NULL) {
        temp = head;
        head = head->next;
        free(temp);
    }
}

Finally, always remember to test the linked list operations. Create a linked list and perform various operations such as inserting and traversing nodes to ensure everything works correctly.

int main() {
    struct Node* head = NULL;
    insertAtEnd(&head, 10);
    insertAtBeginning(&head, 20);
    insertAtEnd(&head, 30);
    freeList(head);
    return 0;
}