1,双向链表相当于两个单向循环链表。
2,双向链表的结点定义。
1 struct DULNode 2 { 3 int data; 4 struct DULNode * prior; 5 struct DULNode * next; 6 }; 7 8 typedef struct DULNode * linklist;
3,单循环链表的操作都适用于双循环链表。
4,双循环链表的操作集合仍在头文件defs.h中。
5,InitList操作。双循环链表初始化操作示意图
1 #include"defs.h" 2 3 void InitList(linklist *L) //改变头指针 4 { 5 *L = (linklist)malloc(sizeof(struct DULNode)); 6 if (*L == NULL) 7 exit(0); 8 (*L)->next = *L; 9 (*L)->prior = *L; 10 }
6,ClearList操作.
1 #include"defs.h" 2 3 void ClearList(linklist L) 4 { 5 linklist p = L->next; //p指向链表第一个元素 6 7 while (p != L) 8 { 9 p = p->next; //p指向第二个元素 10 free(p->prior); 11 } 12 (*L)->next = *L; 13 (*L)->prior = *L; 14 }
7,DestroyList操作
1 #include"defs.h" 2 3 void DestroyList(linklist *L) 4 { 5 ClearList(*L); 6 free(*L); 7 *L = NULL; 8 }
8,ListEmpty操作
1 #include"defs.h" 2 3 int ListEmpty(linklist L) 4 { 5 if (L->next == L && L->prior == L) //两个条件均要有 6 return 0; 7 else 8 return 1; 9 }
9,ListLength操作
1 #include"defs.h" 2 3 int ListLength(linklist L) 4 { 5 linklist p = L->next; 6 int j = 0; 7 8 while (p != L) 9 { 10 ++j; 11 p = p->next; 12 } 13 return j; 14 }
10,GetElem操作
1 #include"defs.h" 2 3 int GetElem(linklist L, int i, int *e) 4 { 5 linklist p = L; 6 int j = 0; 7 if (i<1 || i>ListLength(L)) 8 exit(0); 9 10 while (j<i) //找到第i个结点 11 { 12 ++j; 13 p = p->next; 14 } 15 *e = p->data; 16 }
11,LocateElem操作, 没有找到返回-1
1 #include"defs.h" 2 3 int LocateElem(linklist L, int e) 4 { 5 linklist p = L->next; 6 int j = 0; 7 8 while (p != L) 9 { 10 ++j; 11 if (p->data == e) 12 return j; 13 } 14 return -1; 15 }
12,PriorElem操作
1 #include"defs.h" 2 3 int PriorElem(linklist L, int cur_e, int *pri_e) 4 { 5 linklist p = L->next->next; //p指向第二个元素 6 7 while (p != L) 8 { 9 if (p->data == cur_e) 10 { 11 *pri_e = p->prior->data; 12 return 0; 13 } 14 } 15 return 0; 16 }
13,NextElem操作
1 #include"defs.h" 2 3 int NextElem(linklist L, int cur_e, int *nex_e) 4 { 5 linklist p = L->next->next; 6 7 while (p != L) 8 { 9 if (p->prior->data == cur_e) 10 { 11 *nex_e = p->data; 12 return 0; 13 } 14 } 15 return 0; 16 }
14,ListInsert操作
1 #include"defs.h" 2 3 int ListInsert(linklist L, int i, int e) 4 { 5 linklist p = L; //p指向头结点 6 linklist q, s; 7 int j = 0; 8 if (i<1 || i>ListLength(L)+1) 9 exit(0); 10 11 while (j < i-1) //找到第i-1个结点 12 { 13 ++j; 14 p = p->next; 15 } 16 q = p->next; //q指向第i个结点 17 18 s = (linklist)malloc(sizeof(struct DULNode)); 19 s->data = e; 20 21 s->next = q; //先改变向右的指针 22 p->next = s; 23 s->prior = p; //改变向左的指针 24 q->prior = s; 25 return 0; 26 }
15,ListDelete操作
1 #include"defs.h" 2 3 int ListDelete(linklist L, int i, int *e) 4 { 5 linklist p = L; 6 linklist q; 7 int j = 0; 8 if (i<1 || i>ListLength(L)) //位置是否合理 9 exit(0); 10 11 while (j < i-1) //找到第i-1个元素 12 { 13 ++j; 14 p = p->next; 15 } 16 q = p->next; //p指向第i个结点 17 *e = q->data; 18 19 p->next = q->next; 20 q->next->prior = p; 21 free(q); 22 return 0; 23 }
16,TravelList操作
1 #include"defs.h" 2 3 void TravelList(linklist L) 4 { 5 linklist p = L->next; 6 int j = 0; 7 while (p != L) 8 { 9 ++j; 10 printf("第%d个元素值为:%d ", j, p->data); 11 p = p->next; 12 } 13 }
17,TravelListBack操作,逆序输出表中元素
1 #include"defs.h" 2 3 void TravelListBack(linklist L) 4 { 5 linklist p = L->prior; 6 while (p != L) 7 { 8 printf("%d ", p->data); 9 p = p->prior; 10 } 11 printf(" "); 12 }