链表的操作

#include<stdio.h>
#include<malloc.h>
#include<stdlib.h>
#include<stdbool.h>

typedef struct Node
{
	int data;               //数据域
	struct Node *pNext;     //指针域
}NODE, *PNODE;   //NODE等价于struct Node     PNODE等价于struct Node *

PNODE creat_list(void);
void traverse_list(PNODE);
bool is_empty(PNODE pHead);
int length_list(PNODE pHead);
bool insert_list(PNODE pHead, int pos, int val); //在pHead所指向链表的第pos个节点的前面插入一个新的结点,该节点的值是val,并且pos从1开始
bool delete_list(PNODE pHead, int pos, int *del_val);
void sort_list(PNODE pHead);


int main(void)
{
	PNODE pHead = NULL;     //等价于struct Node * pHead = NULL;
	int len;                //链表的长度
	int del_val;            //删除的值
	pHead = creat_list();   //创建一个非循环链表,并将该链表的头结点的地址赋给pHead
	traverse_list(pHead);   //排序前遍历

	if (is_empty(pHead))
		printf("链表为空\n");
	else
		printf("链表不为空\n");
	len = length_list(pHead);
	printf("链表的长度为:%d\n", len);

	sort_list(pHead);
	printf("排序后遍历\n");
	traverse_list(pHead);  //排序后遍历

	insert_list(pHead, 2, 33);
	printf("插入后遍历\n");
	traverse_list(pHead);  //插入后遍历

	delete_list(pHead, 0, &del_val);
	printf("删除后遍历\n");
	traverse_list(pHead);  //删除后遍历
	return 0;
}

PNODE creat_list(void)
{
	int i;
	int len; //用来存放有效节点的个数
	int val; //用来临时存放用户输入的结点的值
	printf("请输入你需要生成的链表的节点个数:len = ");
	scanf_s("%d", &len);

	PNODE pHead = (PNODE)malloc(sizeof(NODE));//分配了一个不存放数据的头结点
	if (pHead == NULL)
	{
		printf("内存分配失败,程序终止\n");
		exit(-1);
	}

	PNODE pTail = pHead;
	pTail->pNext = NULL;

	for (i = 0; i<len; i++)
	{
		printf("请输入第%d个节点的值:", i + 1);
		scanf_s("%d", &val);

		PNODE pNew = (PNODE)malloc(sizeof(NODE));
		if (pNew == NULL)
		{
			printf("内存分配失败,程序终止\n");
			exit(-1);
		}
		pNew->data = val;
		pTail->pNext = pNew;
		pNew->pNext = NULL;
		pTail = pNew;
	}
	return pHead;
}

void traverse_list(PNODE pHead)
{
	PNODE p = pHead->pNext;
	while (p != NULL)
	{
		printf("%d    ", p->data);
		p = p->pNext;
	}
	printf("\n");
}

bool is_empty(PNODE pHead)
{
	if (pHead->pNext == NULL)
	{
		return true;
	}
	else
	{
		return false;
	}
}

int length_list(PNODE pHead)
{
	int len = 0;
	PNODE p = pHead->pNext;
	while (p != NULL)
	{
		len++;
		p = p->pNext;
	}
	return len;
}

void sort_list(PNODE pHead)
{
	int i;
	int j;
	int len = length_list(pHead);
	int  temp;
	PNODE p;
	PNODE q;

	for (i = 0, p = pHead->pNext; i<len - 1; i++, p = p->pNext) //类似于for(i=0;i<len-1;;i++)
	{
		for (j = 0, q = pHead->pNext; j<len - 1 - i; j++, q = q->pNext)  //类似于for(j=0;j<len-1-i;j++)
		{
			if (q->data > q->pNext->data)       // if(a[j]<a[j+1])
			{
				temp = q->data;
				q->data = q->pNext->data;
				q->pNext->data = temp;
			}
		}
	}
	return;

}

bool insert_list(PNODE pHead, int pos, int val)
{
	int i = 0;
	PNODE p = pHead;

	while (p != NULL && i<pos - 1)              
	{
		p = p->pNext;                      
		i++;                                
	}

	if (i>pos - 1 || p == NULL)               
		return false;                      

	PNODE pNew = (PNODE)malloc(sizeof(NODE));

	if (pNew == NULL)
	{
		printf("动态分配内存(新节点)失败!!!\n");
		exit(-1);
	}

	pNew->data = val;                        
	PNODE q = p->pNext;                    
	p->pNext = pNew;                         
	pNew->pNext = q;                       

	return true;
}

bool delete_list(PNODE pHead, int pos, int *del_val)
{
	int i = 0;
	PNODE p = pHead;

	while (p->pNext != NULL && i<pos - 1)          
	{
		p = p->pNext;                         
		i++;                                
	}

	if (i>pos - 1 || p->pNext == NULL)
		return false;                         

	PNODE q = p->pNext;                     
	*del_val = q->data;                       
	p->pNext = p->pNext->pNext;              
	free(q);                                    .
	q = NULL;                                   .
	return true;
}