dfs.cpp

// C++ program to print DFS traversal for a given given graph 
#include<iostream> 
#include<list> 
using namespace std; 
 
class Graph 
{ 
	int V; // No. of vertices 
	list<int> *adj; // Pointer to an array containing adjacency lists 
	void DFSUtil(int v, bool visited[]); // A function used by DFS 
public: 
	Graph(int V); // Constructor 
	void addEdge(int v, int w); // function to add an edge to graph 
	void DFS(); // prints DFS traversal of the complete graph 
}; 
 
Graph::Graph(int V) 
{ 
	this->V = V; 
	adj = new list<int>[V]; 
} 
 
void Graph::addEdge(int v, int w) 
{ 
     // 1, 
	adj[v].push_back(w); // Add w to v’s list. 
} 
 
void Graph::DFSUtil(int v, bool visited[]) 
{ 
	// Mark the current node as visited and print it 
	visited[v] = true; 
	cout << v << " "; 
 
	// Recur for all the vertices adjacent to this vertex 
	list<int>::iterator i; 
	for(i = adj[v].begin(); i != adj[v].end(); ++i) 
		if(!visited[*i]) 
			DFSUtil(*i, visited); 
} 
 
// The function to do DFS traversal. It uses recursive DFSUtil() 
void Graph::DFS() 
{ 
	// Mark all the vertices as not visited 
	bool *visited = new bool[V]; 
	for (int i = 0; i < V; i++) 
		visited[i] = false; 
 
	// Call the recursive helper function to print DFS traversal 
	// starting from all vertices one by one 
	for (int i = 0; i < V; i++) 
		if (visited[i] == false) 
			DFSUtil(i, visited); 
} 
 
int main() 
{ 
	// Create a graph given in the above diagram 
	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 Traversaln"; 
	g.DFS(); 
 
	return 0; 
}