用dfs非递归算法遍历图。创 建图是用链表来实现。

				// DFS.cpp : Defines the entry point for the console application.
				//
				
				#include 
				#include 
				#define Vnum 20
				typedef struct arcnode          //边结构
				{
					int adjvex;
					struct arcnode *nextarc;
				}arcnode;
				typedef struct vexnode           //顶点
				{
					int vertex;  //编号
					arcnode *firstarc; 
				}adjlist[Vnum];
				typedef struct graphs
				{
					adjlist adj;
					int vexn,arcn;
				}graph;
				void creat(graph *g)
				{
					int n,e,i,j,k;
					arcnode *p;
					cout					cin>>n;
					cout					cin>>e;
					g->vexn=n;g->arcn=e;
					for(i=0;i					{
						g->adj[i].vertex=i;   //编号
						g->adj[i].firstarc=NULL;
					}
					for(k=0;k					{
						cout						cin>>i>>j;
						p=(arcnode *)malloc(sizeof (arcnode));
						p->adjvex=j;
						p->nextarc=g->adj[i].firstarc;
						g->adj[i].firstarc=p;          //将p插在链表的最前边
					}
				}
				
				
				
				void dfs(graph *g,int v)
				{
					int i;
					arcnode *p;
					int visited[Vnum],top=-1,stack[Vnum];
					for(i=0;ivexn;i++)
					{
						visited[i]=0;
					}//初始化标志数组
					cout					top++;
					stack[top]=v;
					visited[v]=1;//将v压入堆栈，标志位置1
					while(top>=0)
					{
						v=stack[top];
						top--;//取栈顶顶点
						p=g->adj[v].firstarc;
						while(p!=NULL && visited[p->adjvex]==1)
						  p=p->nextarc;
						if(p==NULL)
							top--;
						else
						{
							v=p->adjvex;
							cout							visited[v]=1;
							top++;
							stack[top]=v;
						}
					}
				}
					void main()
					{
						graph *g;
						g=(graph*)malloc(sizeof (graph));
						creat(g);
						cout						dfs(g,0);
					}