循环单链表基本操作

#include<iostream>
using namespace std;
#include<malloc.h>

#define ElemType int 

typedef struct LNode
{
    ElemType data;
    struct LNode *next;
}LinkNode;


void InitList(LinkNode *&L)
{
    L=(LinkNode*)malloc(sizeof(LinkNode));
    L->next = L;
}
void CreateListF(LinkNode *&L,ElemType a[],int n)//头插法
{
    LinkNode *p;
    L = (LinkNode * )malloc(sizeof(LinkNode));
    L->next = NULL;
    for(int i = 0;i<n;i++)
    {
        p =(LinkNode * )malloc(sizeof(LinkNode ));
        p->data  = a[i];
        p->next = L->next;
        L->next = p;
    }
    p = L->next;//查找尾结点
    while(p->next != NULL)//p指向尾结点 
    {
        p = p->next;
    }
    p->next = L;//尾结点next指向头结点
}

void CreateListR(LinkNode *&L,ElemType a[],int n)//尾插法
{
    LinkNode *p,*r;
    L = (LinkNode *)malloc(sizeof(LinkNode));
    L->next = NULL;
    r = L;
    for(int i =0;i<n;i++)
    {
        p = (LinkNode *) malloc(sizeof(LinkNode));
        p->data = a[i];
        r->next = p;//将结点p插入r之后
        r = p;
    }
    r ->next =L;//尾结点指向L
}
void DestoryList(LinkNode *&L)
{
    LinkNode *pre = L;
    LinkNode *p =pre->next;
    while(p!=L)
    {
        free(pre);
        pre = p;
        p = p->next;
    }
    free(p);
}

bool ListEmpty(LinkNode *L)
{
    return(L->next ==NULL);
}

int ListLength(LinkNode *L)
{
    LinkNode *p =L;
    int j =0;
    while(p->next != L)
    {
        j++;
        p = p->next; 
    }
    return j;
}

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

bool GetElem(LinkNode *L,int i,ElemType &e)
{
    LinkNode *p = L->next ;
    int j = 0;
    if(i<=0 || L->next ==L) return false;//i错误或为空表
    if(i==1)//求第一个结点的值，特殊处理
    {
        e = L->next->data;
        return true;
    }
    else
    {
        while(j< i-1 && p!=L)
        {
            j++;
            p = p->next;
        }
        if(p==L)
        {
            return false;
        }
        else
        {
            e =p->data;
            return true;
        }
    }
}

int LocateElem(LinkNode *L,ElemType e)
{
    LinkNode * p  = L->next;
    int j = 1;
    while(p!= L && p->data!=e)
    {
        j++;
        p = p->next;
    }
    if( p == L)
    {
        return false;
    }
    else
    {
        return j;
    }
}
bool InsertList(LinkNode *&L,int i ,ElemType e)
{
    LinkNode *p = L;
    LinkNode *s;
    int j = 1;
    if(i <= 0) 
        return false;
    if(p->next == L || i ==1)//原链表为空 或 i==1
    {
        s = (LinkNode *)malloc(sizeof(LinkNode));
        s->data =e ;
        s->next = p->next;
        p->next = s;
        return true;
    }
    else
    {
        p = L->next;
        while( j< i-1 && p !=L)//找到i-1个结点
        {
            j++;
            p = p->next;
        }
        if(p == L)
        {
            return false;
        }
        else
        {
            s = (LinkNode* )malloc(sizeof(LinkNode));
            s->data = e;
            s->next = p->next;
            p->next =s;
            return true;
        }
    }
}


bool ListDelete(LinkNode *&L,int i ,ElemType &e)
{
    int  j =1;
    LinkNode *p =L;
    LinkNode *q;
    if(i <= 0 || L->next == L)
    {
        return false;
    }
    if(i == 1)//i==1 特殊处理
    {
        q = L->next;
        e = q->data;
        L->next = q->next;
        free(q);
        return true;
    }
    else//i不为1时
    {
        p = L->next;
        while(j< i-1 && p!=L)
        {
            j++;
            p = p->next;
        }
        if( p ==L)
        {
            return false;
        }
        else
        {
            q = p->next;
            e = q->data;
            p->next = q->next;
            free(q);
            return true;
        }
    }
}

int main()
{
    LinkNode *h;
    ElemType e;
    cout<<"循环单链表基本操作"<<endl;
    cout<<"初始化"<<endl;
    InitList(h);
    cout<<"依次插入97，98，99，100，101"<<endl;
    InsertList(h,1,97);InsertList(h,2,98);InsertList(h,3,99);InsertList(h,4,100);
    InsertList(h,5,101);
    cout<<"Print"<<endl;
    DispList(h);
    cout<<"Length is "<<ListLength(h)<<endl;

    GetElem(h,3,e);
    cout<<"第3个元素为"<<e<<endl;
    cout<<"在第4个位置上插入 60"<<endl;
    InsertList(h,4,60);
    cout<<"Print "<<endl;
    DispList(h);
    cout<<"删除第3 个元素"<<endl;
    ListDelete(h,3,e);
    cout<<"Print"<<endl;
    DispList(h);
    cout<<"释放循环单链表"<<endl;
    DestoryList(h);
    return 1;
}

运行结果