#include "iostream.h"
  

  const int n=5;
  

  const int e=8;
  

  int visited[n+1]; //访问标志数组
  

  struct link
  

  {
  

  int data;
  

  link *next;
  

  };
  

  struct node
  

  {
  

  int v;     //顶点信息
  

  link *next;
  

  }a[n+1];
  

  

  /* 无向图的建立 */
  

  void createlink()
  

  {
  

  int i,j,k;
  

  link *s;
  

  //初始化
  

  for(i=1;i<=n;i++)
  

  {
  

  a[i].v=i;
  

  a[i].next=NULL;
  

  }
  

  

  /*以头插法建立 */
  

  

  for(k=1;k<=e;k++)
  

  {
  

  cout<<"请输入一条边:";
  

  cin>>i>>j;
  

  cout<<endl;
  

  s=new link;
  

  s->data=j;
  

  s->next=a[i].next;
  

  a[i].next=s;
  

  s=new link;
  

  s->data=i;
  

  s->next=a[j].next;
  

  a[j].next=s;
  

  }
  

  }
  

  

  /* 深度优先搜索 */
  

  void dfs(int i)
  

  {
  

  link *p;
  

  cout<<a[i].v<<" ";
  

  visited[i]=1;
  

  p=a[i].next;
  

  while(p!=NULL)
  

  {
  

  if(!visited[p->data])
  

  dfs(p->data);
  

  p=p->next;
  

  }
  

  }
  

  

  void main()
  

  {
  

  link *p;char yn='y';int k;
  

  createlink();
  

  while(yn=='y')
  

  {
  

  cout<<"你建立的图为:"<<endl;
  

  for(int i=1;i<=n;i++)
  

  {
  

  p=a[i].next;
  

  cout<<a[i].v<<"->";
  

  while(p->next!=NULL)
  

  {
  

  cout<<p->data<<"->";
  

  p=p->next;
  

  }
  

  cout<<p->data<<endl;
  

  }
  

  for(i=1;i<=n;i++)
  

  visited[i]=0;
  

  cout<<"请输入深度优先搜索的顶点:";
  

  cin>>k;
  

  cout<<endl;
  

  

  dfs(k);
  

  cout<<"要继续遍历吗(Y/N)?";
  

  cin>>yn;
  

  }
  

  }