DFS.java

import java.util.InputMismatchException;
import java.util.Scanner;
import java.util.Stack;
 
public class DFS
{
    private Stack<Integer> stack;
 
    public DFS() 
    {
        stack = new Stack<Integer>();
    }
 
    public void dfs(int adjacency_matrix[][], int source)
    {
        int number_of_nodes = adjacency_matrix[source].length - 1;
 
        int visited[] = new int[number_of_nodes + 1];		
        int element = source;		
        int i = source;		
        System.out.print(element + "\t");		
        visited[source] = 1;		
        stack.push(source);
 
        while (!stack.isEmpty())
        {
            element = stack.peek();
            i = element;	
	    while (i <= number_of_nodes)
	    {
     	        if (adjacency_matrix[element][i] == 1 && visited[i] == 0)
	        {
                    stack.push(i);
                    visited[i] = 1;
                    element = i;
                    i = 1;
                    System.out.print(element + "\t");
	            continue;
                }
                i++;
	    }
            stack.pop();	
        }	
    }
 
    public static void main(String...arg)
    {
        int number_of_nodes, source;
        Scanner scanner = null;
 	try
        {
	    System.out.println("Enter the number of nodes in the graph");
            scanner = new Scanner(System.in);
            number_of_nodes = scanner.nextInt();
 
	    int adjacency_matrix[][] = new int[number_of_nodes + 1][number_of_nodes + 1];
	    System.out.println("Enter the adjacency matrix");
	    for (int i = 1; i <= number_of_nodes; i++)
	        for (int j = 1; j <= number_of_nodes; j++)
                    adjacency_matrix[i][j] = scanner.nextInt();
 
	    System.out.println("Enter the source for the graph");
            source = scanner.nextInt(); 
 
            System.out.println("The DFS Traversal for the graph is given by ");
            DFS dfs = new DFS();
            dfs.dfs(adjacency_matrix, source);					
        }catch(InputMismatchException inputMismatch)
        {
            System.out.println("Wrong Input format");
        }	
        scanner.close();	
    }	
}