Find the common nodes in two singly linked list

// C Program 
// Find the common nodes in two singly linked list
#include <stdio.h>
#include <stdlib.h> //for malloc function

// Linked List LinkNode
struct LinkNode
{
  int data;
  struct LinkNode *next;
};
// Singly linked list 
struct SingleLL
{
  struct LinkNode *head;
  struct LinkNode *tail;
};
// Returns the new linked list
struct SingleLL *newLinkedList()
{
  // Create memory of head and tail Nodes
  struct SingleLL *sll = (struct SingleLL *) malloc(sizeof(struct SingleLL));
  if (sll == NULL)
  {
    printf("Memory overflow\n");
  }
  else
  {
    sll->head = NULL;
    sll->tail = NULL;
  }
  return sll;
}
// Add new Node at end of linked list 
void appendNode(struct SingleLL *sll, struct LinkNode *node)
{
  if (sll->head == NULL)
  {
    sll->head = node;
  }
  else
  {
    // Append the node at last position
    sll->tail->next = node;
  }
  sll->tail = node;
}
// Handles the request of adding new node in linked list
void addNode(struct SingleLL *sll, int data)
{
  // Create dynamic node
  struct LinkNode *node = (struct LinkNode *) malloc(sizeof(struct LinkNode));
  if (node == NULL)
  {
    printf("Memory overflow to Create LinkNode\n");
    return;
  }
  else
  {
    // Set initial node value
    node->data = data;
    node->next = NULL;
  }
  appendNode(sll, node);
}
// Display linked list element
void display(struct SingleLL *sll)
{
  if (sll->head == NULL)
  {
    printf("\n Empty linked list\n");
    return;
  }
  struct LinkNode *temp = sll->head;
  // iterating linked list elements
  while (temp != NULL)
  {
    printf(" %d →", temp->data);
    // Visit to next node
    temp = temp->next;
  }
  printf(" NULL\n");
}
// Find common nodes
void findCommonNodes(struct SingleLL *sll1, struct SingleLL *sll2)
{
  if (sll1->head == NULL || sll2->head == NULL)
  {
    return;
  }
  // Display linked list
  printf(" Linked List 1 \n");
  display(sll1);
  // Display linked list
  printf(" Linked List 2 \n");
  display(sll2);
  printf("\n Common Value \n");
  // Get first node of both linked list
  struct LinkNode *auxiliary = sll1->head;
  struct LinkNode *deviation = sll2->head;
  // Define some counter variables 
  int status = 0;
  int counter = 0;
  // iterating linked list elements
  while (auxiliary != NULL)
  {
    // Compare first linked list node to second linked list node value
    while (deviation != NULL)
    {
      if (deviation->data == auxiliary->data)
      {
        // Print common node
        printf("  %d ", auxiliary->data);
        // Like a break operation
        deviation = NULL;
        // Active state because we are got similar node
        status = 1;
        counter++;
      }
      else
      {
        // Visit to next node
        deviation = deviation->next;
      }
    }
    // Visit to next node
    auxiliary = auxiliary->next;
    // Reset second linked position
    // Start to first node of second linked list
    deviation = sll2->head;
  }
  if (status == 0)
  {
    // When no common node exists
    printf(" None \n");
  }
  else
  {
    printf("\n Total common element is : %d\n", counter);
  }
}
int main()
{
  struct SingleLL *sll1 = newLinkedList();
  struct SingleLL *sll2 = newLinkedList();
  // First linked list
  //  3 → 11 → 8 → 5 → -2 → 16 → 9 → NULL
  addNode(sll1, 3);
  addNode(sll1, 11);
  addNode(sll1, 8);
  addNode(sll1, 5);
  addNode(sll1, -2);
  addNode(sll1, 16);
  addNode(sll1, 9);
  // Second linked list
  //  4 → 9 → 7 → 3 → 8 → 6 → -2 → NULL
  addNode(sll2, 4);
  addNode(sll2, 9);
  addNode(sll2, 7);
  addNode(sll2, 3);
  addNode(sll2, 8);
  addNode(sll2, 6);
  addNode(sll2, -2);
  findCommonNodes(sll1, sll2);
  return 0;
}

Output

 Linked List 1
 3 → 11 → 8 → 5 → -2 → 16 → 9 → NULL
 Linked List 2
 4 → 9 → 7 → 3 → 8 → 6 → -2 → NULL

 Common Value
  3   8   -2   9
 Total common element is : 4