Please suggest , unable to find out mistake in this :

Node* Insert(Node *head,int data)
{
Node *temp;
temp->data = data;
temp->next = NULL;

if(head == NULL)
  {
  head = temp;
}
else
  {
  Node *p;
  p = head;
  while(p->next != NULL)
      p = p->next;
  p->next = temp;
}
return(head);
}

Showing no response in output :(