题目：

链式表操作集 带头结点的链式表操作集

函数接口定义：

  1. Position Find( List L, ElementType X );
  2. List Insert( List L, ElementType X, Position P );
  3. List Delete( List L, Position P );

其中List结构定义如下：```c typedef struct LNode *PtrToLNode; struct LNode { ElementType Data; PtrToLNode Next; }; typedef PtrToLNode Position; typedef PtrToLNode List;

  1. 各个操作函数的定义为：<br />Position Find( List L, ElementType X )：返回线性表中首次出现X的位置。若找不到则返回ERROR；<br />List Insert( List L, ElementType X, Position P )：将X插入在位置P指向的结点之前，返回链表的表头。如果参数P指向非法位置，则打印“Wrong Position for Insertion”，返回ERROR；<br />List Delete( List L, Position P )：将位置P的元素删除并返回链表的表头。若参数P指向非法位置，则打印“Wrong Position for Deletion”并返回ERROR。<br /><br /><br />[链接](https://pintia.cn/problem-sets/15/problems/728) | <a name="Jrio3"></a>
  2. ### 函数接口定义：
  3. ```c
  4. List MakeEmpty(); 
  5. Position Find( List L, ElementType X );
  6. bool Insert( List L, ElementType X, Position P );
  7. bool Delete( List L, Position P );

其中List结构定义如下：c typedef struct LNode *PtrToLNode; struct LNode { ElementType Data; PtrToLNode Next; }; typedef PtrToLNode Position; typedef PtrToLNode List; 各个操作函数的定义为：
List MakeEmpty()：创建并返回一个空的线性表；
Position Find( List L, ElementType X )：返回线性表中X的位置。若找不到则返回ERROR；
bool Insert( List L, ElementType X, Position P )：将X插入在位置P指向的结点之前，返回true。如果参数P指向非法位置，则打印“Wrong Position for Insertion”，返回false；
bool Delete( List L, Position P )：将位置P的元素删除并返回true。若参数P指向非法位置，则打印“Wrong Position for Deletion”并返回false。

链接
|

代码：

链式表操作集 带头结点的链式表操作集
#include
#include
#define ERROR NULL
typedef int ElementType;
typedef struct LNode *PtrToNode;
struct LNode
{
ElementType Data;
PtrToNode Next;
};
typedef PtrToNode List;
typedef PtrToNode Position;
void Print();
Position Find(List L, ElementType X);
List Insert(List L, ElementType X, Position P);
List Delete(List L, Position P);







int main()
{
List L;
ElementType X;
Position P, tmp;
int N;
L = NULL;
scanf(“%d”, &N);
while (N—)
{
scanf(“%d”, &X);
L = Insert(L, X, L);
if (L == ERROR)
printf(“Wrong Answer\n”);
}
Print(L);
scanf(“%d”, &N);
while (N—)
{
scanf(“%d”, &X);
P = Find(L, X);
if (P == ERROR)
printf(“Finding Error: %d is not in.\n”, X);
else
{
L = Delete(L, P);
printf(“%d is found and delete.\n”, X);
if (L == ERROR)
{
printf(“Wrong Answer or Empty List.\n”);
}
}
}
L = Insert(L, X, NULL);
if (L == ERROR)
printf(“Wrong Answer\n”);
else
printf(“%d is inserted as the last element.\n”, X);
P = (Position)malloc(sizeof(struct LNode));
tmp = Insert(L, X, P);
if (tmp != ERROR)
printf(“Wrong Answer”);
tmp = Delete(L, P);
if (tmp != ERROR)
printf(“Wrong Answer\n”);
for (P = L; P; P = P->Next)
printf(“%d “, P->Data);
return 0;
}








Position Find(List L, ElementType X)
{
Position tem = L;
while (tem)
{
if (tem->Data == X)
{
return tem;
}
tem = tem->Next;
}
return ERROR;
}
List Insert(List L, ElementType X, Position P)
{
List tem = L;
List current = (List)malloc(sizeof(struct LNode));
current->Data = X;
if (L == P) //头指针 需要处理P为第一个节点的情况
{
current->Next = P;
L = current;
return L;
}
else
{
while (tem)
{
if (tem->Next == P)
{
current->Next = P;
tem->Next = current;
return L;
}
tem = tem->Next;
}
printf(“Wrong Position for Insertion\n”);
return ERROR;
}
}
List Delete(List L, Position P)
{
List tem = L;
if (L == P) //同样需要处理P为第一个节点的情况；
{
L = L->Next;
return L;
}
else
{
while (tem->Next)
{
if (tem->Next == P)
{
tem->Next = P->Next;
free(P);
return L;
}
tem = tem->Next;
}
printf(“Wrong Position for Deletion\n”);
return ERROR;
}
}
void Print(List L)
{
List p = L;
printf(“链表为：”);
while (p)
{
printf(“%d “, p->Data);
p = p->Next;
}
printf(“\n”);
}		 #include
#include
#define ERROR NULL
typedef int ElementType;
typedef struct LNode *PtrToLNode;
typedef enum
{
true,
false
} bool;
struct LNode
{
ElementType Data;
PtrToLNode Next;
};
typedef PtrToLNode List;
typedef PtrToLNode Position;
List MakeEmpty();
Position Find(List L, ElementType X);
bool Insert(List L, ElementType X, Position P);
bool Delete(List L, Position P);
void Print(List L);

int main()
{
List L;
ElementType X;
Position P;
int N;
bool flag;
L = MakeEmpty();
scanf(“%d”, &N);
while (N—)
{
scanf(“%d”, &X);
flag = Insert(L, X, L->Next);
if (flag == false)
printf(“Wrong Answer\n”);
}
Print(L);
scanf(“%d”, &N);
while (N—)
{
scanf(“%d”, &X);
P = Find(L, X);
if (P == ERROR)
printf(“Finding Error: %d is not in.\n”, X);
else
{
flag = Delete(L, P);
printf(“%d is found and delete.\n”, X);
if (flag == false)
printf(“Wrong Answer.\n”);
}
}
flag = Insert(L, X, NULL);
if (flag == false)
printf(“Wrong Answer\n”);
else
printf(“%d is inserted as the last element.\n”, X);
P = (Position)malloc(sizeof(struct LNode));
flag = Insert(L, X, P);
if (flag == true)
printf(“Wrong Answer\n”);
flag = Delete(L, P);
if (flag == true)
printf(“Wrong Answer\n”);
for (P = L->Next; P; P = P->Next)
printf(“%d “, P->Data);
return 0;
}

List MakeEmpty()
{
List L;
L = (List)malloc(sizeof(struct LNode));
L->Next = NULL;
return L;
}

Position Find(List L, ElementType X)
{
List t = L->Next;
while (t)
{
if (t->Data == X)
{
return t;
}
t = t->Next;
}
return ERROR;
}
bool Insert(List L, ElementType X, Position P)
{
List t = L;
List current = (List)malloc(sizeof(struct LNode));
current->Data = X;
while (t)
{
if (t->Next == P)
{
current->Next = P;
t->Next = current;
return true;
}
t = t->Next;
}
printf(“Wrong Position for Insertion\n”);
return false;
}









bool Delete(List L, Position P)
{
List t = L;
while (t)
{
if (t->Next == P)
{
t->Next = P->Next;
free(P);
return true;
}
t = t->Next;
}
printf(“Wrong Position for Deletion\n”);
return false;
}
void Print(List L)
{
List t = L->Next;
printf(“链表为: “);
for (; t; t = t->Next)
{
printf(“%d “, t->Data);
}
printf(“\n”);
}