Deterministic finite automata ( DFA ) implemented using Java....

 

This is a java program to simulate the DFA( deterministic finite automata ) developed using J2SE . It works for any general dfa that you have specified through five tuples during the execution of the program. 

To know that how to give input to the program please click here

here is the code  :-

       

import java.io.*;
import java.util.*;
public class Dfasimulator {

 public int[][] Transition = new int[20][20];
 public int alphaset, stateset;
 public ArrayList < Character > alphabet;
 public Set < Integer > finalstates;

 public void builtdfa() throws Exception {

  BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
  System.out.println("please enter the no. of alphabets in the alphabet set of DFA");
  alphaset = Integer.parseInt(br.readLine());
  //System.out.println(alphaset);
  System.out.println("please enter the no. of states in the set of DFA");
  stateset = Integer.parseInt(br.readLine());

  System.out.println("please enter all the alphabets of the DFA simultaneosly");
  String alphabets = br.readLine();

  alphabet = new ArrayList < Character > ();
  for (int i = 0; i < alphabets.length(); i++) {
   alphabet.add(alphabets.charAt(i));

  }
  //System.out.println(alphabet);

  for (int s = 0; s < stateset; s++) {
   System.out.println("enter the row entries of the transition table");
   for (int r = 0; r < alphaset; r++) {
    int int1 = Integer.parseInt(br.readLine());
    Transition[s][r] = int1;
   }
  }

  finalstates = new HashSet < Integer > ();
  System.out.println("please enter the final states of the DFA\n");
  System.out.println("when you are done of giving the inputs enter -2 to stop feeding final states");

  int int2 = Integer.parseInt(br.readLine());

  while (int2 != -2) {
   finalstates.add(int2);
   int2 = Integer.parseInt(br.readLine());
  }
  System.out.println(finalstates);
  DfaTest();
 }

 public void DfaTest() throws Exception {
  BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
  int state;
  System.out.println("enter the starting state");
  state = Integer.parseInt(br.readLine());

  System.out.println("give input to the DFA\n");
  System.out.println("end your input with # character\n");
  String input = br.readLine();
  int index = 0;

  while (input.charAt(index) != '#') {
   char char1 = input.charAt(index);
   int index1 = alphabet.indexOf(char1);
   state = Transition[state][index1];
   index++;
  }
  System.out.println("\nfinal state after giving the input is " + state);
  if (finalstates.contains(state))
   System.out.print("your input string is accepted by the DFA");
  else
   System.out.println("the input string is rejected by  the DFA");
 }

 public static void main(String args[]) throws Exception {
  Dfasimulator raw = new Dfasimulator();
  raw.builtdfa();
  //System.out.println(raw.alphaset);
 }
}