鏈表指定位置插入，指定位置洗掉，逆置鏈表的練習

指定位置插入：
insert_pos_val(lk headNode, int pos, int val)；

#define _CRT_SECURE_NO_WARNINGS
#include<stdio.h>
#include<stdlib.h>
typedef struct LinkNode
{
	int num;
	LinkNode* next;
}Lk, * lk;
//初始化頭節點
lk init_headNode()
{
	lk headNode = (lk)malloc(sizeof(Lk));
	if (headNode == NULL)
	{
		return NULL;
	}
	headNode->next = NULL;
	//指標遍歷輸出
	lk endNode = headNode;
	//輸入-1結束向鏈表賦值
	int val = -1;
	while (1)
	{
		printf("請輸入：\n");
		scanf("%d", &val);
		if (val == -1)
		{
			break;
		}
		lk newNode = (lk)malloc(sizeof(Lk));
		newNode->num = val;
		newNode->next = NULL;
		//尾插法
		endNode->next = newNode;
		endNode = newNode;
	}
	return headNode;
}
//遍歷輸出
void foreach_linkList(lk headNode)
{
	if (headNode == NULL)
	{
		return;
	}
	lk curNode = headNode->next;
	while (curNode)
	{
		printf("%d\n", curNode->num);
		curNode = curNode->next;
	}
}
//指定位置插入一個值
void insert_pos_val(lk headNode, int pos, int val)
{
	if (headNode == NULL)
	{
		return;
	}
	lk prveNode = headNode;
	lk curNode = headNode->next;
	//索引
	int index = 0;
	while (curNode)
	{
		if (index == pos)
		{
			break;
		}
		prveNode = curNode;
		curNode = curNode->next;
		index++;
	}
	if (pos > index)
	{
		printf("無法插入當前位置\n");
		return;
	}
	lk newNode = (lk)malloc(sizeof(Lk));
	newNode->num = val;
	newNode->next = NULL;
	prveNode->next = newNode;
	newNode->next = curNode;
}
int main()
{
	lk headNode = init_headNode();
	printf("列印輸出鏈表：\n");
	foreach_linkList(headNode);
	printf("插入后列印輸出鏈表：\n");
	insert_pos_val(headNode, 10, 521);
	foreach_linkList(headNode);
	return 0;
}

指定位置洗掉：

#define _CRT_SECURE_NO_WARNINGS
#include<stdio.h>
#include<stdlib.h>
typedef struct LinkNode
{
	int num;
	LinkNode* next;
}Lk, * lk;
//初始化頭節點
lk init_headNode()
{
	lk headNode = (lk)malloc(sizeof(Lk));
	if (headNode == NULL)
	{
		return NULL;
	}
	headNode->next = NULL;
	//指標遍歷輸出
	lk endNode = headNode;
	//輸入-1結束向鏈表賦值
	int val = -1;
	while (1)
	{
		printf("請輸入：\n");
		scanf("%d", &val);
		if (val == -1)
		{
			break;
		}
		lk newNode = (lk)malloc(sizeof(Lk));
		newNode->num = val;
		newNode->next = NULL;
		//尾插法
		endNode->next = newNode;
		endNode = newNode;
	}
	return headNode;
}
//遍歷輸出
void foreach_linkList(lk headNode)
{
	if (headNode == NULL)
	{
		return;
	}
	lk curNode = headNode->next;
	while (curNode)
	{
		printf("%d\n", curNode->num);
		curNode = curNode->next;
	}
}
//指定位置洗掉
void delete_pos_val(lk headNode, int pos, int val)
{
	if (headNode == NULL)
	{
		return;
	}
	lk prveNode = headNode;
	lk curNode = headNode->next;
	//索引：跟據curNode位置移動
	int index = 1;
	while (curNode)
	{
		if (index == pos)
		{
			break;
		}
		prveNode = curNode;
		curNode = curNode->next;
		index++;
	}
	if (pos > index)
	{
		printf("沒有當前元素可供洗掉\n");
		return;
	}
	//改變prveNode指標指向
	prveNode->next = curNode->next;
	//釋放curNode節點在堆區開辟的資料
	free(curNode);
}
int main()
{
	lk headNode = init_headNode();
	printf("列印輸出鏈表：\n");
	foreach_linkList(headNode);
	printf("洗掉后列印輸出鏈表：\n");
	delete_pos_val(headNode, 2, 521);
	foreach_linkList(headNode);
	return 0;
}

逆置鏈表方式：只對當前鏈表進行操作，不借用新鏈表

#define _CRT_SECURE_NO_WARNINGS
#include<stdio.h>
#include<stdlib.h>
typedef struct LinkNode
{
	int num;
	LinkNode* next;
}Lk, * lk;
//初始化頭節點
lk init_headNode()
{
	lk headNode = (lk)malloc(sizeof(Lk));
	if (headNode == NULL)
	{
		return NULL;
	}
	headNode->next = NULL;
	//指標遍歷輸出
	lk endNode = headNode;
	//輸入-1結束向鏈表賦值
	int val = -1;
	while (1)
	{
		printf("請輸入：\n");
		scanf("%d", &val);
		if (val == -1)
		{
			break;
		}
		lk newNode = (lk)malloc(sizeof(Lk));
		newNode->num = val;
		newNode->next = NULL;
		//尾插法
		endNode->next = newNode;
		endNode = newNode;
	}
	return headNode;
}
//遍歷輸出
void foreach_linkList(lk headNode)
{
	if (headNode == NULL)
	{
		return;
	}
	lk curNode = headNode->next;
	while (curNode)
	{
		printf("%d\n", curNode->num);
		curNode = curNode->next;
	}
}
//逆置鏈表
void reverse_pos_val(lk headNode)
{
	if (headNode == NULL)
	{
		return;
	}
	lk prveNode = headNode;
	lk curNode = prveNode->next;
	lk nextNode = curNode->next;
	//第一步：
	prveNode->next = NULL;
	curNode->next = NULL;
	//第二步到第五步
	while (nextNode != NULL)
	{
		//輔助指標往后移動
		prveNode = curNode;
		curNode = nextNode;
		nextNode = nextNode->next;
		//移動過后改變鏈表中curNode節點next指標指向
		curNode->next = prveNode;
	}
   //第六步
	headNode->next = curNode;	
}
int main()
{
	lk headNode = init_headNode();
	printf("列印輸出鏈表：\n");
	foreach_linkList(headNode);
	printf("逆置后列印輸出鏈表：\n");
	reverse_pos_val(headNode);
	foreach_linkList(headNode);
	return 0;
}

方式二：準備一個新鏈表，取出之前鏈表中的元素，用頭插法的方式插入新準備的鏈表中，這里不做演示