C :

#include<stdio.h>
#include<stdlib.h>
#define MAXVEX 60
typedef int WeightType;
typedef int Elemtype;
typedef struct EdgeNode
{
    int adjvex;
	int data;
    WeightType weight;
    struct EdgeNode *next;
}EdgeNode;

typedef struct VexNode
{
    EdgeNode *firstarc;
}VexNode, AdjList[MAXVEX];

typedef struct GraphADJ{
    AdjList adjlist;
    int numvex, numedge;
}GraphADJ;

void InitGraph(GraphADJ *G,int n)
{
    int i;
    G->numvex = n;
    for(i=0; i<n; i++)
	{
		G->adjlist[i].firstarc= NULL;
	}
}
void InsertEdge(GraphADJ *G,int s,int t,int w)
{
    EdgeNode *newn = (EdgeNode *)malloc(sizeof(EdgeNode));
    newn->adjvex = t;
    newn->weight = w;
    newn->next=G->adjlist[s].firstarc;
    G->adjlist[s].firstarc=newn;
	
}
int LocateEdge(GraphADJ G,int s,int t)
{
    EdgeNode *p = G.adjlist[s].firstarc;
    while(p!=NULL)
	{
        if(p->adjvex == t)
            return 0;
        p = p->next;
    }
    return 1;
}
void Create(GraphADJ *G,int n)
{
	int i,j,x,k=0,t;
	int a[60][60],visit[60],b[60];
	InitGraph(G,n);
	for(i=0;i<n;i++)
		visit[i]=0;
	for(i=0;i<n;i++)
		for(j=0;j<n;j++)
	        scanf("%d",&a[i][j]);
	for(i=0;i<n;i++)
		for(j=n-1;j>=0;j--)
		{
            if(a[i][j]==1)
               InsertEdge(G,i,j,1);
		}
	EdgeNode *p;
	i=0;
    while(k==0)
	{
		j=0,t=0;
		printf("%d ",i);
	   do
	   {
	     p=G->adjlist[i].firstarc;
	     visit[i]=1;
	     while(p!=NULL)
		 {
	       i=p->adjvex;
		   if(visit[i]!=1)
		   {
	          b[j++]=i;
              visit[i]=1;
		      printf("%d ",i);
		   }
	       p=p->next;
		 }
	     i=b[t];
		 b[t]=-1;
		 t++;
	   }while(t<=j);
	for(i=0;i<n;i++)
	{
		if(visit[i]==1)
			k=1;
		else
		{
			k=0;
			break;
		}
	}
	}
}
void main()
{
	int n;
	scanf("%d",&n);
	GraphADJ G;
    Create(&G,n);
	printf("\n");
}

Java :

import java.util.LinkedList;
import java.util.Scanner;

public class Main {
   private static Scanner s = new Scanner(System.in) ;
   
   public static void main(String[] args) {
	  int n = s.nextInt() ;
	  int a[][] = new int[n][n] ;
	  for (int i = 0; i < n; i++) {
		for (int j = 0; j < n; j++) {
			a[i][j] = s.nextInt() ;
		}
	  }
	  
	  for (int i = 0; i < a.length; i++) {
		 a[i][i] = 1 ;
	  }
	  
	  boolean visited[] = new boolean[a.length] ;
	  
	  LinkedList<Integer> queue = new LinkedList<Integer>() ;
	  
	  queue.add(0) ;
	  System.out.print(0+ " ") ;
	  visited[0] = true ;
	  
	  while(queue.size()!=0){
		  int k = queue.pollFirst() ;
		  
		  for (int i = 0; i < visited.length; i++) {
			if(visited[i]==false&&a[k][i]==1){
				visited[i] = true ;
				queue.add(i) ;
				System.out.print(i+" ") ;
			}
		  }
	  }
	  System.out.println();
   }
   
   
}