// Abb.java: recognize (a|b)*abb
import java.io.*;
public class Abb {
   private GetChar getChar;
   private char ch;
   private int state = 0;

   public Abb() {
      getChar = new GetChar();
      state = 0;
   }

   public void process() {
      while (true) {
         ch = getChar.getNextChar();
         if (ch == '$') break; // out of while
         switch (state) {
         case 0: if (ch == 'a') state = 1;
                 else if (ch == 'b') state = 0;
                 break;
         case 1: if (ch == 'a') state = 1;
                 else if (ch == 'b') state = 2;
                 break;
         case 2: if (ch == 'a') state = 1;
                 else if (ch == 'b') state = 3;
                 break;
         case 3: if (ch == 'a') state = 1;
                 else if (ch == 'b') state = 0;
                 break;
         }
         System.out.print("ch: " + ch + ", next state: "
            + state);
         if (state == 3) System.out.print(" Terminal");
         System.out.print("\n");
      }
      if (state == 3) System.out.print("Accept\n");
      else System.out.print("Reject\n");
   }

   public static void main(String[] args) {
      Abb abb = new Abb();
      abb.process();
   }
}
/*
/home/neal/java_sdk/jdk1.5.0_08/bin/javac Abb.java
/home/neal/java_sdk/jdk1.5.0_08/bin/java Abb
*/