Merge pull request #1 from SupulCFG/c_dev

Added C - Linked List

Data Structures/LinkedList/linked_list.c

@@ -0,0 +1,180 @@
+
+#include <stdio.h>
+#include <stdlib.h>
+
+
+//self referencing structure with one data element
+struct Node {
+    int data;
+    struct Node *next;
+};
+
+
+// Aliasing for easier referencing
+typedef struct Node Node; 
+
+/*-------------------------------------- Linked List Functions -------------------------------------- */
+/** Ideally these should go in a seperate Header file (ie. linked_list.h) along with the self referencing structures 
+ * 
+ * Linked List Functions
+ * Create Node  : create_node
+ * Insert       : insert_head, insert_tail, insert_next_to
+ * Update       : update
+ * Search       : search
+ * Delete       : delete
+ * Display List : print_list
+ * 
+ */
+
+// Creates a Node in Heap and returns a pointer
+Node * create_node(int data){
+    Node *node = malloc(1 * sizeof(Node));
+    node->data = data;
+    node->next = NULL;
+
+    return node;
+}
+
+// Searches for the given value and returns the node if found
+Node * search(Node *head, int value) {
+
+    while(head != NULL) {
+        if(head->data == value) {
+            return head;
+        }
+
+        head = head->next;
+    }
+
+    return NULL;
+}
+
+
+// appends a node to the end of the Linked List
+void insert_tail(Node **head, int data) {
+    if(*head == NULL) {
+        *head = create_node(data);
+    }else {
+        Node *current = *head;
+
+        while(current->next != NULL) {
+            current = current->next;
+        }
+
+        current->next = create_node(data);
+    }
+}
+
+// appends a node to the beginning of the Linked List
+void insert_head(Node **head, int data) {
+    Node *new_node = create_node(data);
+
+    new_node->next = *head;
+    *head =  new_node;
+}
+
+// appends the node next to the node with given value 
+void insert_next_to(Node *head, int next_to, int data) {
+    Node *search_result = search(head, next_to);
+
+    if(search_result != NULL) {
+        Node *new_node = create_node(data);
+
+        new_node->next = search_result->next;
+        search_result->next = new_node;
+    }else {
+        printf("Insert Failed : No such value found!!\n");
+    }
+}
+
+// Updates specific element in the Linked List
+void update(Node *head, int old_value, int new_value) {
+    Node *search_result = search(head, old_value);
+
+    if(search_result != NULL) {
+        search_result->data = new_value;
+    }else {
+        printf("Update Failed : Value not found!!\n");
+    }
+}
+
+// looks for (int value) and deletes the first node containing (int value) if found 
+int delete(Node **head, int value) {
+    if(*head == NULL) {
+        printf("Delete Faied : Empty List\n");
+        return -1;
+    }
+
+    Node *current = *head;
+    Node *previous = NULL;
+
+    while(current != NULL) {
+        if(current->data == value) {
+            break;
+        }
+
+        previous = current;
+        current = current->next;
+    }
+
+    if(current == NULL) {
+        printf("Delete Faied : Value not found!!\n");
+        return -1;
+    }else {
+        if(current == *head) {
+            *head = (*head)->next;
+        }else {
+            previous->next = current->next;
+        }
+
+        int deleted = current->data;
+
+        free(current);
+
+        printf("Successfully deleted %d\n", deleted);
+
+        return deleted;
+    }
+}
+
+
+// Prints all the elements in the linked list
+void print_list(Node *head) {
+    if(head == NULL) {
+        printf("Empty List !!\n"); 
+    }else {
+
+        printf("[");
+
+        while(head != NULL) {
+            printf(" %d", head->data);
+
+            if(head->next != NULL) printf(",");
+
+            head = head->next;
+        }
+
+        printf(" ]\n");
+    }
+}
+
+/* --------------------------------- End of Linked List Functions ----------------------------------- */
+
+int main() {
+    Node *head = NULL;      // Pointer to the First Node of the Linked List
+
+    insert_tail(&head, 10);
+    insert_tail(&head, 50);
+
+    insert_head(&head, 5);
+
+    insert_next_to(head, 10, 11);
+
+    update(head, 10, 19);
+
+    delete(&head, 19);
+
+    print_list(head);
+
+    return 0;
+}