To implement breadth first search algorithm

import java.io.*;
import java.util.*;
//--------------------------------------------------------------------------------
class Nodetype
{
int info;
   Arctype arcptr;
   Nodetype nextnode;
   Nodetype(int i)
{
info=i;
arcptr=null;
nextnode=null;
}
}
//--------------------------------------------------------------------------------
class Arctype
{

   Nodetype nodeptr;
   Arctype nextarc;
   Arctype()
{
nodeptr=null;
nextarc=null;
}
}
//--------------------------------------------------------------------------------



class Queue
{
/*array is used to hold queue elements*/
/*two integer variables are used for front and rear pointers*/
int items[]=new int[10];
int front,rear;

Queue()
{/*create queue*/
front=0;
rear=-1;
}/*end createqueue*/


void insert(int e)
{/*if queue is not full insert new element at rear end of queue*/
if(rear==9)
System.out.println("Queue overflow");
else
items[++rear]=e;
}/*end insert*/

int empty()
{/*Return 1 if queue is empty and 0 otherwise*/
return(rear<front? 1:0);
}/*end empty*/

int remove()
{/*if queue is not empty remove one element from front */

int x=0;
if(empty()==1)
{
System.out.println("Queue Underflow");
return 0;
}
else
{
x=items[front++];
return x;
}
/*end else*/
}/*end rem*/
}
//-------------------------------------------------------------------------------

class Operations
{
Nodetype graph=null;

void insertnode(int x)
{
/*insert new node at the end of linked graph*/

Nodetype node=new Nodetype(x);
Nodetype temp;
temp=graph;
if(temp==null)
graph=node;
else
{
while(temp.nextnode!=null)
temp=temp.nextnode;
temp.nextnode=node;
}
}/*end insertnode*/


void insertarc(int i)
{
/*insert new node at the end of linked graph*/
int x,ans;
Nodetype temp1,temp2;
Arctype temp3=null;

temp1=searchnode(i);
do
{
System.out.print("\nEnter adjacent node for node "+i+ " : ");
x=getNumber();
temp2=searchnode(x);
if (temp2!=null)
{
Arctype node=new Arctype();
node.nodeptr=temp2;
node.nextarc=null;

if (temp1.arcptr==null)
temp1.arcptr=node;
else
{
temp3=temp1.arcptr;
while (temp3.nextarc!=null)
temp3=temp3.nextarc;
temp3.nextarc=node;
}
}
System.out.print("\nContinue to add adjacent node for "+i+"(1/0)?");
ans=getNumber();
}while(ans==1);

System.out.print("\nNode "+i+ "is connected to : ");
temp3=temp1.arcptr;
do
{
System.out.print(" "+(temp3.nodeptr).info);
temp3=temp3.nextarc;
}while (temp3!=null);

}/*end insertarc*/


Nodetype searchnode(int x)
{
/*search an element in linked graph and return its location*/
int i=1;
Nodetype q;
if(graph==null)
{
System.out.println("\nList is empty");
return null;
}
else
{
q=graph;
do
{
if(q.info==x)
break;
i++;
q=q.nextnode;
}
while(q!=null);
if(q==null)
{
System.out.println("\nNode not found");
return null;
}
else
return q;
}
}/*end searchnode*/

int  adjacent(int u,int i)
{
int x,ans;
Nodetype temp1,temp2;
Arctype temp3=null;
temp1=searchnode(u);
temp3=temp1.arcptr;
do
{
if ((temp3.nodeptr).info==i)
return 1;
else
temp3=temp3.nextarc;
}while (temp3!=null);
return 0;
}/*end adjacent*/

void creategraph()
{
int i,n=0,x,ans1,initial_node;
System.out.println("Enter no. of nodes : ");
n=getNumber();
for(i=1;i<=n;i++)
insertnode(i);
for(i=1;i<=n;i++)
insertarc(i);
System.out.println("\nEnter the initial node for BFS traversal:");
initial_node=getNumber();
BFS(initial_node,n);
}/*end creategraph*/

void BFS (int initial_node,int n)
{
Queue q=new Queue();
int u,i;
u = initial_node;
int visited[]=new int[n+1];

visited[initial_node]=1;
System.out.println("\nBFS traversal for given graph is : ");
System.out.print(initial_node);
q.insert(initial_node);
while(q.empty()==0)
{
u = q.remove();
 for (i=1;i<=n;i++)
{
if((adjacent(u,i)==1) && (visited[i]==0))
{
 q.insert(i);
 visited[i]=1;
 System.out.print(" "+i);
}
 }
}
} /* end of BFS function    */


int getNumber()
{
String str;
int ne=0;
InputStreamReader input=new InputStreamReader(System.in);
BufferedReader in=new BufferedReader(input);
try
{
str=in.readLine();
ne=Integer.parseInt(str);
}
catch(Exception e)
{
System.out.println("I/O Error");
}
return ne;
}

}
//-------------------------------------------------------------------------------

class Graph_Linked
{
public static void main(String args[])
{
Operations L =new Operations();
L.creategraph();
}
}

/*
Enter no. of nodes :
9

Enter adjacent node for node 1 : 2

Continue to add adjacent node for 1(1/0)?1

Enter adjacent node for node 1 : 3

Continue to add adjacent node for 1(1/0)?0

Node 1is connected to :  2 3
Enter adjacent node for node 2 : 1

Continue to add adjacent node for 2(1/0)?1

Enter adjacent node for node 2 : 4

Continue to add adjacent node for 2(1/0)?1

Enter adjacent node for node 2 : 5

Continue to add adjacent node for 2(1/0)?0

Node 2is connected to :  1 4 5
Enter adjacent node for node 3 : 1

Continue to add adjacent node for 3(1/0)?1

Enter adjacent node for node 3 : 5

Continue to add adjacent node for 3(1/0)?0

Node 3is connected to :  1 5
Enter adjacent node for node 4 : 2

Continue to add adjacent node for 4(1/0)?1

Enter adjacent node for node 4 : 6

Continue to add adjacent node for 4(1/0)?1

Enter adjacent node for node 4 : 7

Continue to add adjacent node for 4(1/0)?0

Node 4is connected to :  2 6 7
Enter adjacent node for node 5 : 2

Continue to add adjacent node for 5(1/0)?1

Enter adjacent node for node 5 : 3

Continue to add adjacent node for 5(1/0)?1

Enter adjacent node for node 5 : 8

Continue to add adjacent node for 5(1/0)?0

Node 5is connected to :  2 3 8
Enter adjacent node for node 6 : 4

Continue to add adjacent node for 6(1/0)?1

Enter adjacent node for node 6 : 9

Continue to add adjacent node for 6(1/0)?0

Node 6is connected to :  4 9
Enter adjacent node for node 7 : 4

Continue to add adjacent node for 7(1/0)?0

Node 7is connected to :  4
Enter adjacent node for node 8 : 5

Continue to add adjacent node for 8(1/0)?0

Node 8is connected to :  5
Enter adjacent node for node 9 : 6

Continue to add adjacent node for 9(1/0)?0

Node 9is connected to :  6
Enter the initial node for BFS traversal:
1

BFS traversal for given graph is :
1 2 3 4 5 6 7 8 9
*/