DFS in graph

#include<iostream>
#include<list>
using namespace std;

class graph{
  public:
      int v;
      list<int> *adj;
      graph(int vertex){
        v=vertex;
        adj=new list<int>[v];
        }
      void AddEdge(int v1,int v2){
        adj[v1].push_back(v2);
        }
  };

void DFSUtil(graph g,int start, bool visit[]){
  visit[start]=true;
  cout<<start<<" ";
  list<int>:: iterator ptr;
  for(ptr=g.adj[start].begin();ptr!=g.adj[start].end();ptr++){
    if(visit[*ptr]==false)
        DFSUtil(g,*ptr,visit);
     }
  }

void DFS(graph g,int start){
  int vertex=g.v;
  bool visit[vertex];
  for(int i=0;i<vertex;i++)
    visit[i]=false;
  DFSUtil(g,start,visit);
  }

int main(){
    graph g(4);
    g.AddEdge(0, 1);
    g.AddEdge(0, 2);
    g.AddEdge(1, 2);
    g.AddEdge(2, 0);
    g.AddEdge(2, 3);
    g.AddEdge(3, 3);
    cout << "Following is Depth First Traversal"
            " (starting from vertex 2) \n";
    DFS(g,2);
    return 0;
    }

/*  second method. DFS as member function of graph class
class graph{
  public:
      int v;
      list<int> *adj;
      graph(int vertex){
        v=vertex;
        adj=new list<int>[v];
        }
      void AddEdge(int v1,int v2){
        adj[v1].push_back(v2);
        adj[v2].push_back(v1);
        }

      void DFSUtil(int start, bool visit[]){
         visit[start]=true;
         cout<<start<<" ";
         list<int> ::iterator i;
         for(i=adj[start].begin();i!=adj[start].end();i++){
             if(visit[*i]==false)
                 DFSUtil(*i,visit);
             }
          }

      void DFS(int start){
           bool visit[v];
           for(int i=0;i<v;i++)
                visit[i]=false;
           DFSUtil(start,visit);
           }

  };
*/