diff --git a/DS/C/Lab/Week8/DLLAdd.c b/DS/C/Lab/Week8/DLLAdd.c
new file mode 100644
index 0000000..d086b04
--- /dev/null
+++ b/DS/C/Lab/Week8/DLLAdd.c
@@ -0,0 +1,82 @@
+// Write a program to implement addition of two long positive integer numbers using doubly linked list.
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#define MAX_DIGITS 100
+
+typedef struct node {
+    int digit;
+    struct node *left;
+    struct node *right;
+} Node;
+
+Node* createNode(int digit) {
+    Node* newNode = (Node*)malloc(sizeof(Node));
+    newNode->digit = digit;
+    newNode->left = NULL;
+    newNode->right = NULL;
+    return newNode;
+}
+
+void insertDigit(Node** head, int digit) {
+    Node* newNode = createNode(digit);
+    if (*head == NULL) {
+        *head = newNode;
+    } else {
+        newNode->right = *head;
+        (*head)->left = newNode;
+        *head = newNode;
+    }
+}
+
+void addNumbers(Node* num1, Node* num2, Node** result) {
+    int carry = 0, sum;
+    Node *ptr1 = num1, *ptr2 = num2;
+
+    while (ptr1 || ptr2 || carry) {
+        sum = carry;
+        if (ptr1) {
+            sum += ptr1->digit;
+            ptr1 = ptr1->right;
+        }
+        if (ptr2) {
+            sum += ptr2->digit;
+            ptr2 = ptr2->right;
+        }
+        insertDigit(result, sum % 10);
+        carry = sum / 10;
+    }
+}
+
+void printNumber(Node* head) {
+    if (head == NULL) return;
+    printNumber(head->right);
+    printf("%d", head->digit);
+}
+
+int main() {
+    Node *num1 = NULL, *num2 = NULL, *result = NULL;
+    char str[MAX_DIGITS];
+    int i;
+
+    printf("Enter first number: ");
+    scanf("%s", str);
+    for (i = 0; str[i] != '\0'; i++) {
+        insertDigit(&num1, str[i] - '0');
+    }
+
+    printf("Enter second number: ");
+    scanf("%s", str);
+    for (i = 0; str[i] != '\0'; i++) {
+        insertDigit(&num2, str[i] - '0');
+    }
+
+    addNumbers(num1, num2, &result);
+
+    printf("Sum: ");
+    printNumber(result);
+    printf("\n");
+
+    return 0;
+}
diff --git a/DS/C/Lab/Week8/DLLConcat.c b/DS/C/Lab/Week8/DLLConcat.c
new file mode 100644
index 0000000..bea89b0
--- /dev/null
+++ b/DS/C/Lab/Week8/DLLConcat.c
@@ -0,0 +1,78 @@
+//Write a program to concatenate two doubly linked lists X1 and X2. After
+// concatenation X1 is a pointer to first node of the resulting lists.
+
+#include <stdio.h>
+#include <stdlib.h>
+
+typedef struct node {
+    int data;
+    struct node *llink;
+    struct node *rlink;
+} *node_pointer;
+
+void concatenate(node_pointer *X1, node_pointer *X2) {
+    node_pointer temp;
+    if (*X1 == NULL) {
+        *X1 = *X2;
+    } else if (*X2 != NULL) {
+        temp = *X1;
+        while (temp->rlink != NULL)
+            temp = temp->rlink;
+        temp->rlink = *X2;
+        (*X2)->llink = temp;
+    }
+}
+
+node_pointer create_node(int data) {
+    node_pointer new_node = (node_pointer)malloc(sizeof(struct node));
+    new_node->data = data;
+    new_node->llink = NULL;
+    new_node->rlink = NULL;
+    return new_node;
+}
+
+void insert_end(node_pointer *head, int data) {
+    node_pointer new_node = create_node(data);
+    if (*head == NULL) {
+        *head = new_node;
+    } else {
+        node_pointer temp = *head;
+        while (temp->rlink != NULL)
+            temp = temp->rlink;
+        temp->rlink = new_node;
+        new_node->llink = temp;
+    }
+}
+
+void print_list(node_pointer head) {
+    node_pointer temp = head;
+    while (temp != NULL) {
+        printf("%d ", temp->data);
+        temp = temp->rlink;
+    }
+    printf("\n");
+}
+
+int main() {
+    node_pointer X1 = NULL, X2 = NULL;
+
+    insert_end(&X1, 1);
+    insert_end(&X1, 2);
+    insert_end(&X1, 3);
+
+    insert_end(&X2, 4);
+    insert_end(&X2, 5);
+
+    printf("X1: ");
+    print_list(X1);
+    printf("X2: ");
+    print_list(X2);
+
+    concatenate(&X1, &X2);
+
+    printf("After concatenation:\n");
+    printf("X1: ");
+    print_list(X1);
+
+    return 0;
+}
diff --git a/DS/C/Lab/Week8/DLLUnionIntersec.c b/DS/C/Lab/Week8/DLLUnionIntersec.c
new file mode 100644
index 0000000..5030bed
--- /dev/null
+++ b/DS/C/Lab/Week8/DLLUnionIntersec.c
@@ -0,0 +1,90 @@
+// Write a program to implement union and intersection of two doubly linked lists.
+
+#include <stdio.h>
+#include <stdlib.h>
+
+struct node {
+    int data;
+    struct node *prev;
+    struct node *next;
+};
+
+typedef struct node *NODE;
+
+NODE getnode() {
+    NODE x;
+    x = (NODE)malloc(sizeof(struct node));
+    if(x == NULL) {
+        printf("Out of memory\n");
+        exit(0);
+    }
+    return x;
+}
+
+void insert_rear(NODE *head, int item) {
+    NODE temp, cur;
+    temp = getnode();
+    temp->data = item;
+    temp->next = NULL;
+    if(*head == NULL) {
+        temp->prev = NULL;
+        *head = temp;
+        return;
+    }
+    cur = *head;
+    while(cur->next != NULL)
+        cur = cur->next;
+    cur->next = temp;
+    temp->prev = cur;
+}
+
+NODE union_lists(NODE head1, NODE head2) {
+    NODE result = NULL;
+    NODE temp = head1;
+    while(temp != NULL) {
+        insert_rear(&result, temp->data);
+        temp = temp->next;
+    }
+    temp = head2;
+    while(temp != NULL) {
+        NODE cur = result;
+        int found = 0;
+        while(cur != NULL) {
+            if(cur->data == temp->data) {
+                found = 1;
+                break;
+            }
+            cur = cur->next;
+        }
+        if(!found)
+            insert_rear(&result, temp->data);
+        temp = temp->next;
+    }
+    return result;
+}
+
+NODE intersection_lists(NODE head1, NODE head2) {
+    NODE result = NULL;
+    NODE temp = head1;
+    while(temp != NULL) {
+        NODE cur = head2;
+        while(cur != NULL) {
+            if(temp->data == cur->data) {
+                insert_rear(&result, temp->data);
+                break;
+            }
+            cur = cur->next;
+        }
+        temp = temp->next;
+    }
+    return result;
+}
+
+void display(NODE head) {
+    NODE temp = head;
+    while(temp != NULL) {
+        printf("%d ", temp->data);
+        temp = temp->next;
+    }
+    printf("\n");
+}
diff --git a/DS/C/Lab/Week8/DoublyLL.c b/DS/C/Lab/Week8/DoublyLL.c
new file mode 100644
index 0000000..8e52c3d
--- /dev/null
+++ b/DS/C/Lab/Week8/DoublyLL.c
@@ -0,0 +1,256 @@
+//Write a menu driven program to perform the following on a doubly linked list
+//DS LAB MANUAL
+// i.) Insert an element at the rear end of the list
+// ii.) Delete an element from the rear end of the list
+// iii.) Insert an element at a given position of the list
+// iv.) Delete an element from a given position of the list
+// v.) Insert an element after another element
+// vi.) Insert an element before another element
+// vii.) Traverse the list
+// viii.) Reverse the list
+
+#include <stdio.h>
+#include <stdlib.h>
+
+struct Node {
+    int data;
+    struct Node* prev;
+    struct Node* next;
+};
+
+struct Node* head = NULL;
+
+void insertRear(int data) {
+    struct Node* newNode = (struct Node*)malloc(sizeof(struct Node));
+    newNode->data = data;
+    newNode->next = NULL;
+
+    if (head == NULL) {
+        newNode->prev = NULL;
+        head = newNode;
+        return;
+    }
+
+    struct Node* temp = head;
+    while (temp->next != NULL)
+        temp = temp->next;
+
+    temp->next = newNode;
+    newNode->prev = temp;
+}
+
+void deleteRear() {
+    if (head == NULL) {
+        printf("List is empty\n");
+        return;
+    }
+
+    if (head->next == NULL) {
+        free(head);
+        head = NULL;
+        return;
+    }
+
+    struct Node* temp = head;
+    while (temp->next != NULL)
+        temp = temp->next;
+
+    temp->prev->next = NULL;
+    free(temp);
+}
+
+void insertPosition(int data, int position) {
+    struct Node* newNode = (struct Node*)malloc(sizeof(struct Node));
+    newNode->data = data;
+
+    if (position == 1) {
+        newNode->prev = NULL;
+        newNode->next = head;
+        if (head != NULL)
+            head->prev = newNode;
+        head = newNode;
+        return;
+    }
+
+    struct Node* temp = head;
+    for (int i = 1; i < position - 1 && temp != NULL; i++)
+        temp = temp->next;
+
+    if (temp == NULL) {
+        printf("Position out of range\n");
+        return;
+    }
+
+    newNode->next = temp->next;
+    newNode->prev = temp;
+    if (temp->next != NULL)
+        temp->next->prev = newNode;
+    temp->next = newNode;
+}
+
+void deletePosition(int position) {
+    if (head == NULL) {
+        printf("List is empty\n");
+        return;
+    }
+
+    struct Node* temp = head;
+
+    if (position == 1) {
+        head = head->next;
+        if (head != NULL)
+            head->prev = NULL;
+        free(temp);
+        return;
+    }
+
+    for (int i = 1; i < position && temp != NULL; i++)
+        temp = temp->next;
+
+    if (temp == NULL) {
+        printf("Position out of range\n");
+        return;
+    }
+
+    temp->prev->next = temp->next;
+    if (temp->next != NULL)
+        temp->next->prev = temp->prev;
+    free(temp);
+}
+
+void insertAfter(int data, int key) {
+    struct Node* newNode = (struct Node*)malloc(sizeof(struct Node));
+    newNode->data = data;
+
+    struct Node* temp = head;
+    while (temp != NULL && temp->data != key)
+        temp = temp->next;
+
+    if (temp == NULL) {
+        printf("Key not found\n");
+        return;
+    }
+
+    newNode->next = temp->next;
+    newNode->prev = temp;
+    if (temp->next != NULL)
+        temp->next->prev = newNode;
+    temp->next = newNode;
+}
+
+void insertBefore(int data, int key) {
+    struct Node* newNode = (struct Node*)malloc(sizeof(struct Node));
+    newNode->data = data;
+
+    if (head == NULL) {
+        printf("List is empty\n");
+        return;
+    }
+
+    if (head->data == key) {
+        newNode->next = head;
+        newNode->prev = NULL;
+        head->prev = newNode;
+        head = newNode;
+        return;
+    }
+
+    struct Node* temp = head;
+    while (temp->next != NULL && temp->next->data != key)
+        temp = temp->next;
+
+    if (temp->next == NULL) {
+        printf("Key not found\n");
+        return;
+    }
+
+    newNode->next = temp->next;
+    newNode->prev = temp;
+    temp->next->prev = newNode;
+    temp->next = newNode;
+}
+
+void traverse() {
+    struct Node* temp = head;
+    while (temp != NULL) {
+        printf("%d ", temp->data);
+        temp = temp->next;
+    }
+    printf("\n");
+}
+
+void reverse() {
+    struct Node* temp = NULL;
+    struct Node* current = head;
+
+    while (current != NULL) {
+        temp = current->prev;
+        current->prev = current->next;
+        current->next = temp;
+        current = current->prev;
+    }
+
+    if (temp != NULL)
+        head = temp->prev;
+}
+
+int main() {
+    int choice, data, position, key;
+
+    while (1) {
+        printf("\n1. Insert at rear\n2. Delete from rear\n3. Insert at position\n");
+        printf("4. Delete from position\n5. Insert after element\n6. Insert before element\n");
+        printf("7. Traverse\n8. Reverse\n9. Exit\n");
+        printf("Enter your choice: ");
+        scanf("%d", &choice);
+
+        switch (choice) {
+            case 1:
+                printf("Enter data to insert: ");
+                scanf("%d", &data);
+                insertRear(data);
+                break;
+            case 2:
+                deleteRear();
+                break;
+            case 3:
+                printf("Enter data to insert: ");
+                scanf("%d", &data);
+                printf("Enter position: ");
+                scanf("%d", &position);
+                insertPosition(data, position);
+                break;
+            case 4:
+                printf("Enter position to delete: ");
+                scanf("%d", &position);
+                deletePosition(position);
+                break;
+            case 5:
+                printf("Enter data to insert: ");
+                scanf("%d", &data);
+                printf("Enter element after which to insert: ");
+                scanf("%d", &key);
+                insertAfter(data, key);
+                break;
+            case 6:
+                printf("Enter data to insert: ");
+                scanf("%d", &data);
+                printf("Enter element before which to insert: ");
+                scanf("%d", &key);
+                insertBefore(data, key);
+                break;
+            case 7:
+                traverse();
+                break;
+            case 8:
+                reverse();
+                break;
+            case 9:
+                exit(0);
+            default:
+                printf("Invalid choice\n");
+        }
+    }
+
+    return 0;
+}