BFS implementation using Java

import java.io.*;
class quelist
{
  public int front;
  public int rear;
  public int maxsize;
  public int que[];
  public quelist(int size)
  {
    maxsize = size;
    que = new int[size];
    front = rear = -1;
  }
  public void enque(int x)
  {
     if(front==-1)
     front = 0;
     que[(++rear)%maxsize]=x;
  }
  public int deque()
  {
    int temp = que[front];
    front = (front +1)%maxsize;
    return temp;
  }
   public boolean isempty()
  {
    return((front>rear)||(front==-1));
  }
}  
class vertex
{
 public char label;
 public boolean wasvisited;
 public vertex(char lab)
 {
   label = lab;
   wasvisited = false;
 }
}
class graph
{
  public final int MAX = 20;
  public int nverts;
  public int adj[][];
  public vertex vlist[];
  quelist qu;
  public graph()
  {
   nverts = 0;
   vlist = new vertex[MAX];
   adj = new int[MAX][MAX];
   qu = new quelist(MAX);
   for(int i=0;i<MAX;i++)
    for(int j=0;j<MAX;j++)
     adj[i][j] = 0;
  }
  public void addver(char lab)
  {
    vlist[nverts++] = new vertex(lab);
  }
  public void addedge(int start,int end)
  {
    adj[start][end] = 1;
    adj[end][start] = 1;
  }
  public int getadjunvis(int i)
  {
    for(int j=0;j<nverts;j++)
      if((adj[i][j]==1)&&(vlist[j].wasvisited==false))
      return j;
    return (MAX+1);  
  }
  public int getind(char l)
  {
    for(int i=0;i<nverts;i++)
      if(vlist[i].label==l)
      return i;
    return (MAX+1);
  }
  public void brfs()
  {
    vlist[0].wasvisited = true;
    System.out.print(vlist[0].label);
    qu.enque(0);
    int v2;
    while(!(qu.isempty()))
    {
     int v1 = qu.deque();
     while((v2=getadjunvis(v1))!=(MAX+1))
      {
    vlist[v2].wasvisited = true;
        System.out.print(vlist[v2].label);
        qu.enque(v2);
      }  
    }
    System.out.print("\n");
  }
}



class bfs
{
  public static void main(String args[])throws IOException
  {
    graph gr = new graph();
    InputStreamReader isr = new InputStreamReader(System.in);
    BufferedReader br = new BufferedReader(isr);
    System.out.println("Enter the number of vertices");
    int n = Integer.parseInt(br.readLine());
if(n<=20)
 {
System.out.println("Enter the labels for the vertices");
for(int i=0;i<n;i++)
{
 String temp = br.readLine();
 char ch = temp.charAt(0);
 gr.addver(ch);
}
System.out.println("Enter the number of edges");
int edg = Integer.parseInt(br.readLine());
System.out.println("Enter the vertices which you need to connect");
for(int j=0;j<edg;j++)
{
 System.out.println("Enter the first vertex");
 String t = br.readLine();
 char c = t.charAt(0);
 int start = gr.getind(c);

 System.out.println("Enter the second vertex");
 t = br.readLine();
 c = t.charAt(0);
 int end = gr.getind(c);

 gr.addedge(start,end);
}
System.out.print("The vertices in the graph traversed breadthwise:");
gr.brfs();
 }
 else
 {
 System.out.println("Enter the number of vertex less than 20");
 }
  }
}