循環鏈表

//帶頭節點
#include <iostream>
using namespace std;
typedef int ElemType;

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

void InitList(LinkList &L);
void CreateCyList(LinkList l);
void Output(LinkList l);
int ListLength(LinkList l);
bool PreElem(LinkList l,ElemType e,ElemType &pre);
LinkList MergeCyList(LinkList La,LinkList lb);

int main(int argc, char const *argv[])
{
	/*
    LinkList l;
    InitList(l);
    CreateCyList(l);
    Output(l);
    cout<<"len:"<<ListLength(l)<<endl;
    int x;
    if(PreElem(l,20,x)==true)
    cout<<"20的前驅元素爲"<<x<<endl;
    */
    LinkList l1,l2;
    InitList(l1);
    InitList(l2);
    CreateCyList(l1);
    CreateCyList(l2);
    LinkList p = MergeCyList(l1,l2);
    Output(p);
	return 0;
}

void InitList(LinkList &L)
{
    L = new LNode;
    L->next = L;
}

void CreateCyList(LinkList l)
{
    cout<<"請依次輸入數據，並以-1作爲結束標記:\n";
        int m;
    LNode *p = l;
    while(1)
    {
        cin>>m;
        if(m==-1)
            break;
        LNode *s = new LNode;
        s->data = m;
        p->next = s;
        p = s;
    }
    p->next = l;
}


void Output(LinkList l)
{
    LNode *p;
    p = l->next;
    while(p!=l)
    {
        cout<<p->data<<" ";
        p = p->next;
    }
    cout<<"\n";
}

int ListLength(LinkList l)
{
    LNode *p;
    p = l->next;
    int len = 0;
    while(p!=l)
    {
        len++;
        p = p->next;
    }
    return len;
}

bool PreElem(LinkList l,ElemType e,ElemType &pre)
{
    LNode *p,*q;
    p = l->next;
    q = p->next;
    while(q!=l->next)
    {
        if(q->data==e)
        {
            pre = p->data;
            return true;
        }
            p = q;
            q = q->next;
    }
    return false;
}

LinkList MergeCyList(LinkList La,LinkList Lb)
{
    LNode *p,*q;
    p=La,q=Lb;
    while(p->next!=La) 	p = p->next;
    while(q->next!=Lb) 	q = q->next;
    q->next = La;
	p->next = Lb->next; 
	
	delete Lb;
    return La;
}