Graph : BFS and DFS

import java.io.*;
import java.util.*;
class Graph
{
  int v[][],q[];
  boolean flag[];
  int rear=-1,front=-1,size,v1,v2;
 
  Graph(int siz)
  {
    size=siz;
    v=new int[size][size];
    q=new int[size];
    flag=new boolean[size];
    for(int i=0;i<size;i++)
    {
 for(int j=0;j<size;j++)
      {
  v[i][j]=0;  
 }
 q[i]=0;
 flag[i]=false;
}
  }
 
  void create()throws Exception
  {
     DataInputStream di=new DataInputStream(System.in);
     char ch='y';
do
     {
   System.out.println("\nEnter the edges of graph : ");
v1=Integer.parseInt(di.readLine());
v2=Integer.parseInt(di.readLine());
v[v1][v2]=1;
v[v2][v1]=1;
System.out.println("\nDo you want to enter more edges(y/n):");
   String s=di.readLine();
        ch=s.charAt(0);
}while(ch!='n');
  }
  void mat()throws Exception
  {
    System.out.println("\nMatrix for the Graph is:\n");  
    for(int i=0;i<size;i++)
    {
 for(int j=0;j<size;j++)
      {
  System.out.print(v[i][j]+"  ");  
 }
 System.out.println();
}
  }
 
  void bfs(int x)throws Exception
  {
     rear++;
q[rear]=x;
flag[rear]=true;
for(int i=0;i<size;i++)
     {
  x=q[++front];
  System.out.println(x);
  for(int j=0;j<size;j++)
       {
         if(v[x][j]==1 && flag[j]==false)
{
 flag[j]=true;
 q[++rear]=j;
   }
   }
     }
for(int i=0;i<size;i++)
    {
  flag[i]=false;
}
  }
 
  void dfs(int i)throws Exception
  {
    System.out.println(i);
flag[i]=true;
for(int j=0;j<size;j++)
    {
      if(v[i][j]==1&&flag[j]==false)
 {
   dfs(j);
    }
}
  }
 
  public static void main(String args[ ])throws Exception
  {
     int siz,x;
DataInputStream dis=new DataInputStream(System.in);
System.out.print("\nEnter total no of vertices: ");  
siz=Integer.parseInt(dis.readLine());
Graph g=new Graph(siz);
try
{
  g.create();
  g.mat();
  System.out.println("\nBreadth First Search Traversal");
  System.out.print("\nEnter vertex from which you want to traverse:");
  x=Integer.parseInt(dis.readLine());
  g.bfs(x);
  System.out.println("\nDepth First search Traversal");    
       System.out.print("\nEnter vertex from which you want to traverse:");
  x=Integer.parseInt(dis.readLine());
  g.dfs(x);
            
}
catch(Exception e)
{}
  }
}

/*
OUTPUT


C:\java\bin>javac Graph.java

C:\java\bin>java Graph

Enter total no of vertices: 4

Enter the edges of graph :
0
1

Do you want to enter more edges(y/n):
y

Enter the edges of graph :
0
2

Do you want to enter more edges(y/n):
y

Enter the edges of graph :
1
3

Do you want to enter more edges(y/n):
y

Enter the edges of graph :
2
3

Do you want to enter more edges(y/n):
n

Matrix for the Graph is:

0  1  1  0
1  0  0  1
1  0  0  1
0  1  1  0

Breadth First Search Traversal

Enter vertex from which you want to traverse:0
0
1
2
3

Depth First search Traversal

Enter vertex from which you want to traverse:0
0
1
3
2
*/