DFS implementation using Java

import java.io.*;
class stcklist
{
  public int top;
  public int maxsize;
  public int[] stck;

  public stcklist(int size)
  {
    maxsize = size;
    stck = new int[size];
    top= -1;
  }

  public void push(int x)
  {
     stck[++top]=x;
  }

  public int pop()
  {
    int temp = stck[top];
    top--;
    return temp;
  }
  public int top()
  {
    int temp = stck[top];
    return temp;
  }
  public boolean isempty()
  {
    return(top==-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[];
  stcklist st;

  public graph()
  {
   nverts = 0;
   vlist = new vertex[MAX];
   adj = new int[MAX][MAX];
   st = new stcklist(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 drfs()
  {
    vlist[0].wasvisited = true;
    System.out.print(vlist[0].label);
    st.push(0);
    int v2;
    while(!(st.isempty()))
    {
     int v1 = st.top();
// v2=getadjunvis(v1));
     if((v2=getadjunvis(v1))!=(MAX+1))
      {
    vlist[v2].wasvisited = true;
        System.out.print(vlist[v2].label);
        st.push(v2);
      }
 else
 st.pop();
    }
  }
}



class dfs
{
  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());
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.drfs();
  }
}