head 8 bidlist.c ret->head = NULL; head 24 bidlist.c if(blist->head == NULL){ head 25 bidlist.c blist->head = newnode; head 45 bidlist.c blist->head = next; head 58 bidlist.c bidnode* point = blist->head; head 66 bidlist.c blist->mark = blist-> head; head 12 bidlist.h bidnode* head;