6-5 带头结点的链式表操作集

List MakeEmpty() {
    List dummy = (List)malloc(sizeof(Position));
    dummy->Data = -1;
    dummy->Next = NULL;
    return dummy;
}

Position Find( List L, ElementType X ) {
    while(L) {
        if(L->Data == X) return L;
        else L = L->Next;
    }
    return NULL;
}

bool Insert( List L, ElementType X, Position P ) {
    List p = (List)malloc(sizeof(Position));
    p->Data = X;
    while(L) {
        if(L->Next == P) {
            p->Next = P;
            L->Next = p;
            return true;
        }else L = L->Next;
    }
    printf("Wrong Position for Insertion\n");
    return false;
}

bool Delete( List L, Position P ) {
    while(L->Next) {
        if(L->Next == P) {
            L->Next = L->Next->Next;
            return true;
        }else L = L->Next;
    }
    printf("Wrong Position for Deletion\n");
    return false;
}