Finding loop in a singly linked-list

Question

How can I detect that whether a singly linked-list has loop or not?? If it has loop then how to find the point of origination of the loop i.e. the node from which the loop

Answer 1

                bool FindLoop(struct node *head)
                {
                    struct node *current1,*current2;

                    current1=head;
                    current2=head;

                    while(current1!=NULL && current2!= NULL && current2->next!= NULL)
                    { 
                          current1=current1->next;
                          current2=current2->next->next;

                          if(current1==current2)
                          {
                                return true;
                          }
                    }

                    return false;
                }