单链表的基本操作

#include <cstdio>
#include <cstdlib>
#include <iostream>
using namespace std;

typedef char ElemType;
#define ERROR -1
#define OK 1

typedef struct Node{
	ElemType data;
	struct Node *next;
}Node, *LinkList;

LinkList CreateList()
{
	LinkList L;
	char c;
	Node *r, *s;
	int flag = 1;
	L = (LinkList)malloc(sizeof(Node));
	L->next = NULL;
	r = L;
	while(flag)
	{
		cin >> c;
		if(c != '#')
		{
			s = (Node *)malloc(sizeof(Node));
			s->data = c;
			r->next = s;
			r = s;
		}
		else
		{
			flag = 0;
			r->next = NULL;
		}
	}
	return L;
}

void PrintList(Node *L)
{
	Node *p;
	p = L->next;
	while(p != NULL)
	{
		cout << p->data << " " ;
		p = p->next;
	}
	cout << endl;
}

Node * GetList(LinkList L, int i)
{
	int j;
	Node *p;
	if( i <= 0)
	{
		return NULL;
	}
	p = L;
	j = 0;
	while(p->next != NULL && j < i)
	{
		p = p->next;
		j++;
	}
	if(i == j)
	{
		return p;
	}
	else
	{
		return NULL;
	}
}

Node * LocateList(LinkList L, ElemType e)
{
	Node *p;
	p = L->next;
	while(p != NULL)
	{
		if(p->data != e)
		{
			p = p->next;
		}
		else
		{
			break;
		}
	}
	return p;
}

int InsertList(LinkList L, int i, ElemType e)
{
	Node *pre, *s;
	int k;
	if(i <= 0)
	{
		return ERROR;
	}
	pre = L;
	k = 0;
	while(pre != NULL && k < i - 1)
	{
		pre = pre->next;
		k++;
	}
	if(!pre)
	{
		printf("输入的位置不合理！\n");
		return ERROR;
	}
	s = (Node *)malloc(sizeof(Node));
	s->data = e;
	s->next = pre->next;
	pre->next = s;
	return OK;
}

int DeleteList(LinkList L, int i)
{
	Node *pre , *r;
	int k;
	pre = L;
	k = 0;
	while(pre->next != NULL && k < i - 1)
	{
		pre = pre->next;
		k++;
	}
	if(!(pre->next))
	{
		printf("删除的位置不合理！\n");
		return ERROR;
	}
	r = pre->next;
	pre->next = r->next;
	free(r);
	return OK;
}

int listLength(LinkList L)
{
	int j;
	Node *p;
	p = L->next;
	j = 0;
	while(p != NULL)
	{
		p = p->next;
		j++;
	}
	return j;
}

void FreeList(LinkList L)
{
	if(L->next != NULL)
	{
		FreeList(L->next);
	}
	free(L);
}

int scan()
{
	int n;
	cout << "-----------------++++++++++++++++++-------------------" << endl;
	cout << "                请选择所要进行的操作                  " << endl;
	cout << "1、链表的生成，输入#终止                              " << endl;
	cout << "2、输出链表的长度                                     " << endl;
	cout << "3、遍历链表的元素                                     " << endl;
	cout << "4、按序号查找      5、按值查找                        " << endl;
	cout << "6、链表元素的插入  7、链表元素的删除                  " << endl;
	cout << "-----------------++++++++++++++++++-------------------" << endl;
	cin >> n;
	return n;
}

int main()
{
	LinkList L;
	int quit = 0;
	int i;
	ElemType e;
	Node *p;
	while(!quit)
	{
		switch(scan())
		{
			case 1 : L = CreateList();break;
			case 2 : cout << "链表的长度为：" << listLength(L) << endl << endl;break;
			case 3 : PrintList(L);break;
			case 4 : cout << "请输入要查找的序号" << endl; cin >> i; p = GetList(L,i);cout << "查找的元素为：" << p->data << endl;break;
			case 5 : cout << "请输入要查找的元素" << endl; cin >> e; p = LocateList(L,e);break;
			case 6 : cout << "请输入要插入的元素和位置" << endl; cin >> e >> i;InsertList(L,i,e);break;
			case 7 : cout << "请输入要删除的元素的位置" << endl; cin >> i; DeleteList(L,i);break;
			default: quit = 1;
		}
	}
	return 0;
}