Linked List Added Issur Number #228

C/LinkedList.c

@@ -0,0 +1,139 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+//Defination of a Linked List using pointers
+struct Node {
+    int data;
+    struct Node *next;
+};
+
+
+//Creates a Node and allocates into Heap memory 
+struct Node *createNode(int data){
+    struct Node *newNode = (struct Node *) malloc(sizeof(struct Node ));
+    newNode->data = data;
+    newNode->next = NULL;
+    return newNode;
+}
+
+void traverse(struct Node *head){
+    printf("\n");
+    struct Node* current = head;
+    while (current != NULL)
+    {
+        printf("%d\n" , current->data);
+        current = current->next;
+    }
+
+}
+// Function to insert a node at the end of the linked list
+//Taking Double Pointer so as to change the head if required
+void insertAtEnd(struct Node** head_ref, int new_data) {
+    struct Node* new_node = (struct Node*)malloc(sizeof(struct Node));
+    struct Node* last = *head_ref;
+
+    new_node->data = new_data;
+    new_node->next = NULL;
+
+
+    //if head is NULL
+    if (*head_ref == NULL) {
+        *head_ref = new_node;
+        return;
+    }
+
+    while (last->next != NULL) {
+        last = last->next;
+    }
+    last->next = new_node;
+}
+
+// Function to insert a node after a given previous node
+void insertAfter(struct Node* prev_node, int new_data) {
+    if (prev_node == NULL) {
+        printf("The given previous node cannot be NULL");
+        return;
+    }
+
+    struct Node* new_node = (struct Node*)malloc(sizeof(struct Node));
+    new_node->data = new_data;
+    new_node->next = prev_node->next;
+    prev_node->next = new_node;
+}
+
+
+
+// Function to delete the first occurrence of a given key in the linked list
+void deleteAtMiddle(struct Node** head_ref, int key) {
+    struct Node* temp = *head_ref;
+    struct Node* prev = NULL;
+
+    // If the head node itself holds the key to be deleted
+    if (temp != NULL && temp->data == key) {
+        *head_ref = temp->next;
+        free(temp);
+        return;
+    }
+
+    // Search for the key to be deleted, keeping track of the previous node
+    while (temp != NULL && temp->data != key) {
+        prev = temp;
+        temp = temp->next;
+    }
+
+    // If the key was not present in the list
+    if (temp == NULL) return;
+
+    // Unlink the node from the linked list
+    prev->next = temp->next;
+    free(temp);
+}
+
+
+// Function to delete the last node of the linked list
+void deleteAtEnd(struct Node** head_ref) {
+    if (*head_ref == NULL) return;
+
+    struct Node* temp = *head_ref;
+    struct Node* prev = NULL;
+
+    // If there is only one node in the list
+    if (temp->next == NULL) {
+        free(temp);
+        *head_ref = NULL;
+        return;
+    }
+
+    // Traverse to the last node
+    while (temp->next != NULL) {
+        prev = temp;
+        temp = temp->next;
+    }
+
+    // Unlink the last node
+    prev->next = NULL;
+    free(temp);
+}
+
+
+int main(){
+    struct Node* head = malloc(sizeof(struct Node)) ;
+    head->data = 1;
+    insertAtEnd(&head, 2);
+    insertAtEnd(&head, 3);
+    insertAtEnd(&head, 4);
+    printf("Linked List after insertion: ");
+    traverse(head);
+
+    // Delete node with data 3
+    deleteAtMiddle(&head, 3);
+    printf("Linked List after deleting node with data 3: ");
+    traverse(head);
+
+    // Delete at end
+    deleteAtEnd(&head);
+    printf("Linked List after deleting at end: ");
+    traverse(head);
+
+    return 0;
+}