数据结构入门——链表的实现

标签：数据结构   链表   算法   

    该程序实现了链表的增、删、遍历、排序等大部分功能，仅供参考。理解链表的原理，对后面栈、队列、二叉树、图等数据结构的学习有很大帮助。

链表的实现：

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

typedef struct Node
{
	int data;
	struct Node * pNext;
}NODE, *PNODE;

PNODE create_list(void);
void traverse_list(const PNODE);
bool is_empty(PNODE);
int length_list(PNODE);
bool sort_list(PNODE);
bool insert_list(PNODE);
bool delete_list(PNODE);

int main(void)
{
	PNODE pHead = (PNODE)malloc(sizeof(NODE));

	pHead = create_list();
	traverse_list(pHead);
	is_empty(pHead);
	int len = length_list(pHead);
	printf("链表的长度为：%d\n", len);
	printf("排序后：\n");
	sort_list(pHead);
	traverse_list(pHead);
	insert_list(pHead);
	traverse_list(pHead);
	delete_list(pHead);
	traverse_list(pHead);

	return 0;
}

PNODE create_list(void)
{
	int i;
	int val;
	int len;

	PNODE pHead = (PNODE)malloc(sizeof(NODE));
	PNODE pTail = pHead;
	pTail->pNext = NULL;

	printf("请输入节点的个数：len = ");
	scanf("%d", &len);

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

		PNODE pNew = (PNODE)malloc(sizeof(NODE));
		if (NULL == pNew)
		{
			printf("内存空间分配失败！\n");
			exit(-1);
		}
		pNew->data = val;
		pTail->pNext = pNew;
		pNew->pNext = NULL;
		pTail = pNew;
	}

	return pHead;
}

void traverse_list(const PNODE pHead)
{
	PNODE p = pHead->pNext;

	if(NULL == p)
	{
		printf("链表为空！\n");
		return;
	}

	printf("\n链表中的数据为：\n");
	while (NULL != p)
	{
		printf("%d  ", p->data);
		p = p->pNext;
	}
	printf("\n");

	return;
}

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

int length_list(PNODE pHead)
{
	int len = 0;
	PNODE p = pHead;

	while (NULL != p->pNext)
	{
		++len;
		p = p->pNext;
	}

	return len;
}

bool sort_list(PNODE pHead)
{
	int i, j;
	int t;
	int len;
	PNODE p, q;

	if ( is_empty(pHead) )
	{
		printf("链表为空！\n");
		return false;
	}
	else
	{
		len = length_list(pHead);
		for (i=0, p=pHead->pNext; i<len-1; ++i, p=p->pNext)
		{
			for (j=i+1, q=p->pNext; j<len; ++j, q=q->pNext)
			{
				if (p->data > q->data)
				{
					t = p->data;
					p->data = q->data;
					q->data = t;
				}
			}
		}
		return true;
	}
}

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

	printf("请输入您要插入的位置：pos = ");
	scanf("%d", &pos);

	//判断输入位置pos的正确性并使指针后移，使指针p指向最后一个结点。此语句非常经典！
	while (NULL!=p && i<pos-1)
	{
		p = p->pNext;
		++i;
	}

	if (i>pos-1 || NULL==p)  //判断位置的正确性及指针p的是否为空，防止程序崩溃。
	{
		printf("输入错误，插入失败！\n");
		return false;
	}

	printf("请输入您要插入的数据：val = ");
	scanf("%d", &val);

	PNODE pNew = (PNODE)malloc(sizeof(NODE));
	if (NULL == pNew)
	{
		printf("内存分配失败！\n");
		exit(-1);
	}

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

	return true;
}

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

	printf("请输入您要删除的位置：pos = ");
	scanf("%d", &pos);

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

	if (NULL==p->pNext || i>pos-1)
	{
		printf("输入错误，删除失败！\n");
		return false;
	}

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

	//删除p后面的结点
	p->pNext = p->pNext->pNext;
	free(q);
	q = NULL;

	printf("删除成功，您删除的数据为：%d", val);
}

数据结构入门——链表的实现

标签：数据结构   链表   算法   

原文地址：http://blog.csdn.net/lfhappypain/article/details/47292771