#include<stdio.h>
#include<Windows.h>


typedef int ElemType;
typedef struct LNode {
	ElemType data;
	LNode* next;

}LNode, * ListPoint;


//ListPoint InitList();初始化單鏈表
//ListPoint List_HeadInsert(ListPoint &L);頭插法建立單鏈表
//ListPoint List_TailInsert(ListPoint &L);尾插法建立單鏈表
//LNode* GetElem(ListPoint L, int i);按序號查詢結點值
//LNode* LocateElem(ListPoint L, ElemType e); 按值查詢表結點
//ListPoint List_Insert(ListPoint L,, int i, ElemType e) 指定位置插入
//ListPoint DeleteElem(ListPoint L,);刪除結點
//int Length(ListPoint L);求表長
//void PrintList(ListPoint L);列印


//ListPoint InitList();初始化單鏈表,建立代空表頭的連結串列
ListPoint InitList() {
	ListPoint L = (ListPoint)malloc(sizeof(LNode));
	L->next = NULL;
	return L;
}

//void List_HeadInsert(ListPoint L, ElemType e);頭插法建立單鏈表
void List_HeaderInsert(ListPoint L, ElemType e) {
	LNode* newNode = (LNode*)malloc(sizeof(LNode));
	newNode->data = e;
	newNode->next = L->next;
	L->next = newNode;
}

//void List_TailInsert(ListPoint L, ElemType e);尾插法建立單鏈表
void List_TailInsert(ListPoint L, ElemType e) {
	LNode* newNode = (LNode*)malloc(sizeof(LNode));
	LNode* tailNode = L;
	while (tailNode->next) {
		tailNode = tailNode->next;
	}
	newNode->data = e;
	newNode->next = NULL;
	tailNode->next = newNode;
	tailNode = newNode;
}

//LNode* GetElem(ListPoint L, int i);按序號查詢結點值
LNode* GetElem(ListPoint L, int i) {
	if (i < 0)
		return NULL;
	else if (i == 0)
		return L;
	L = L->next;
	int index = 1;
	while (L && index < i) {
		L = L->next;
		index++;
	}
	return L;
}

//LNode* LocateElem(ListPoint L, ElemType e); 按值查詢表結點
LNode* LocateElem(ListPoint L, ElemType e) {
	L = L->next;
	while (L) {
		if (L->data == e) {
			return L;
		}
		L = L->next;
	}
	return NULL;
}

//ListPoint List_Insert(ListPoint L,, int i, ElemType e) 指定位置插入
ListPoint List_Insert(ListPoint L, int i, ElemType e) {
	LNode* forthNode;
	if ((forthNode = GetElem(L, i-1))) {
		LNode* newNode = (LNode*)malloc(sizeof(LNode));
		newNode->data = e;
		newNode->next = forthNode->next;
		forthNode->next = newNode;
		return newNode;
	}
	return NULL;
}

//ListPoint DeleteElem(ListPoint L, int i);刪除結點
ElemType DeleteElem(ListPoint L, int i) {
	LNode* forthNode;
	if ((forthNode = GetElem(L, i - 1)) && forthNode->next) {
		LNode* delNode = forthNode->next;
		forthNode->next = delNode->next;
		ElemType i = delNode->data;
		free(delNode);
		return i;
	}
	return NULL;
}

//int Length(ListPoint L);求表長
int Length(ListPoint L) {
	int count = 0;
	L = L->next;
	while (L) {
		count++;
		L = L->next;
	}
	return count;
}

//void DestoryList(ListPoint L); 刪除整個連結串列
void DestoryList(ListPoint L) {
	
}


//void PrintList(ListPoint L);列印
void PrintList(ListPoint L) {
	L = L->next;
	while (L){
		printf("%3d", L->data);
		L = L->next;
	}
	putchar('\n');
}


int main(int argc, char* argv) {
	ListPoint L = InitList();
	PrintList(L);
	printf("連結串列總長度:%d\n", Length(L));
	for (int i = 0; i < 5; i++) {
		List_HeaderInsert(L, i);
	}
	for (int i = 10; i < 17; i++) {
		List_TailInsert(L, i);
	}
	PrintList(L);
	printf("連結串列總長度:%d\n", Length(L));

	LNode* node1 = GetElem(L,12);
	if (node1) {
		printf("第10個元素是%i\n", node1->data);
	}
	LNode*  node2= LocateElem(L, 12);
	if (node2) {
		printf("找到了\n");
	}
	else {
		printf("沒找到\n");
	}

	List_Insert(L, 0, 0);
	List_Insert(L, 1, 1);
	List_Insert(L, 2, 2);
	List_Insert(L, 100, 1);
	PrintList(L);
	List_Insert(L, 15, 19);
	PrintList(L);

	DeleteElem(L, -1);
	PrintList(L);
	DeleteElem(L, 0);
	PrintList(L);
	DeleteElem(L, 1);
	PrintList(L);
	DeleteElem(L, 10);
	PrintList(L);
	DeleteElem(L, 13);
	PrintList(L);
	DeleteElem(L, 100);
	PrintList(L);

	system("pause");
	return 0;
}