线性表带头结点的单链表的链式表示和实现

带有头结点的单链表的12个基本操作

#define DestroyList ClearList//DestroyList()和ClearList()的操作是一样的

void InitList(LinkList &L){
    L = NULL;
}

void ClearList(LinkList &L){
    LinkList p;
    while (L){
        p = L;
        L = L->next;
        free(p);
    }
}

Status ListEmpty(LinkList L){
    if (L)return FALSE;
    else return TRUE;
}

int ListLength(LinkList L){
    LinkList p = L;
    int i = 0;
    while (p)
    {
        i++;
        p = p->next;
    }
    return i;
}

Status GetElem(LinkList L, int i, ElemType &e){
    int j = 1;
    LinkList p = L;
    if (i < 1)return ERROR;
    while (j < i && p){
        j++;
        p = p->next;
    }
    if (j == i && p){
        e = p->data;
        return OK;
    }
    return ERROR;
}

int LocateElem(LinkList L, ElemType e, Status(*compare)(ElemType, ElemType)){
    int i = 1;
    LinkList p = L;
    while (p){
        i++;
        if (compare(p->data, e))
            return i;
        p = p->next;
    }
    return 0;
}

Status PriorElem(LinkList L, ElemType cur_e, ElemType &pre_e){
    LinkList q, p = L;
    while (p->next){
        q = p->next;
        if (q->data == cur_e){
            pre_e = p->data;
            return OK;
        }
        p = q;
    }
}

Status NextElem(LinkList L, ElemType cur_e, ElemType &next_e){
    LinkList p = L;
    while (p->next){
        if (p->data == cur_e){
            next_e = p->next->data;
            return OK;
        }
        p = p->next;
    }
    return ERROR;
}

Status ListInsert(LinkList L, int i, ElemType e){
    int j = 1;
    LinkList s, p = L;
    if (i < 1)return ERROR;
    s = (LinkList)malloc(sizeof(LNode));
    s->data = e;
    if (i == 1){
        s->next = L;
        L = s;
    }
    else
    {
        while (p && j < i - 1){
            j++;
            p = p->next;
        }
        if (!p)return ERROR;
        s->next = p->next;
        p->next = s;
    }
    return OK;
}

Status ListDelete(LinkList L, int i, ElemType &e){
    int j = 1;
    LinkList q, p = L;
    if (!L)return ERROR;
    else if (i == 1){
        L = p->next;
        e = p->data;
        free(p);
    }
    else
    {
        while (p->next && j < i - 1){
            j++;
            p = p->next;
        }
    }
    if (!p->next || j > i - 1){
        return  ERROR;
        q = p->next;
        p->next = q->next;
        e = q->data;
        free(q);
    }
    return OK;
}

void ListTraverse(LinkList L, void(*visit)(ElemType&)){
    LinkList p =L;
    while (p)
    {
        visit(p->data);
        p = p->next;
    }
    printf("\n");
}