Tutoriais - Linguagens Formais e Autômatos
Tutoriais
Linguagens Formais e Autômatos

/*************************************************************************
 * Copyright (C) 2009/2025 - Cristiano Lehrer (cristiano@ybadoo.com.br)  *
 *                  Ybadoo - Solucoes em Software Livre (ybadoo.com.br)  *
 *                                                                       *
 * Permission is granted to copy, distribute and/or modify this document *
 * under the terms of the GNU Free Documentation License, Version 1.3 or *
 * any later version published by the  Free Software Foundation; with no *
 * Invariant Sections,  no Front-Cover Texts, and no Back-Cover Texts. A *
 * A copy of the  license is included in  the section entitled "GNU Free *
 * Documentation License".                                               *
 *                                                                       *
 * Ubuntu 16.10 (GNU/Linux 4.8.0-39-generic)                             *
 * OpenJDK Version "1.8.0_121"                                           *
 * OpenJDK 64-Bit Server VM (build 25.121-b13, mixed mode)               *
 *************************************************************************/

package com.ybadoo.tutoriais.lfa.tutorial02.exercicio03;

import java.util.HashMap;
import java.util.Map;

/**
 * Estado do Automato Finito Deterministico
 */
public class State
{
  /**
   * Estado eh de aceitacao
   */
  private boolean accept;

  /**
   * Transicao de estados
   */
  private Map<Character, Integer> transitions;

  /**
   * Constructor
   *
   * @param accept estado eh de aceitacao
   */
  public State(boolean accept)
  {
    this.accept = accept;

    transitions = new HashMap<>();
  }

  /**
   * Retornar se o estado eh de aceitacao
   *
   * @return true se o estado eh de aceitacao,
   *   false em caso contrario
   */
  public boolean isAccept()
  {
    return accept;
  }

  /**
   * Adicionar uma transicao de estado
   *
   * @param symbol simbolo corrente
   * @param state novo estado
   */
  public void addTransition(Character symbol, Integer state)
  {
    transitions.put(symbol, state);
  }

  /**
   * Retornar o novo estado
   *
   * @param symbol simbolo corrente
   * @return novo estado
   */
  public Integer getTransition(Character symbol)
  {
    return transitions.get(symbol);
  }
}

/*************************************************************************
 * Copyright (C) 2009/2025 - Cristiano Lehrer (cristiano@ybadoo.com.br)  *
 *                  Ybadoo - Solucoes em Software Livre (ybadoo.com.br)  *
 *                                                                       *
 * Permission is granted to copy, distribute and/or modify this document *
 * under the terms of the GNU Free Documentation License, Version 1.3 or *
 * any later version published by the  Free Software Foundation; with no *
 * Invariant Sections,  no Front-Cover Texts, and no Back-Cover Texts. A *
 * A copy of the  license is included in  the section entitled "GNU Free *
 * Documentation License".                                               *
 *                                                                       *
 * Ubuntu 16.10 (GNU/Linux 4.8.0-39-generic)                             *
 * OpenJDK Version "1.8.0_121"                                           *
 * OpenJDK 64-Bit Server VM (build 25.121-b13, mixed mode)               *
 *************************************************************************/

package com.ybadoo.tutoriais.lfa.tutorial02.exercicio03;

import java.util.HashMap;
import java.util.Map;

/**
 * Automato Finito Deterministico (AFD)
 */
public class DeterministicFiniteAutomaton
{
  /**
   * Estados do Automato Finito Deterministico (AFD)
   */
  private Map<Integer, State> states;

  /**
   * Constructor
   */
  public DeterministicFiniteAutomaton()
  {
    states = new HashMap<>();

    State q0 = new State(false);
    q0.addTransition('i', 0);
    q0.addTransition('j', 0);
    q0.addTransition('k', 1);
    states.put(0, q0);

    State q1 = new State(false);
    q1.addTransition('i', 2);
    q1.addTransition('j', 0);
    q1.addTransition('k', 1);
    states.put(1, q1);

    State q2 = new State(false);
    q2.addTransition('i', 0);
    q2.addTransition('j', 0);
    q2.addTransition('k', 3);
    states.put(2, q2);

    State q3 = new State(true);
    q3.addTransition('i', 2);
    q3.addTransition('j', 0);
    q3.addTransition('k', 1);
    q3.addTransition('$', 3);
    states.put(3, q3);
  }

  /**
   * Formatar o estado para impressao
   *
   * @param state estado
   * @return estado formatado para impressao
   */
  private String formatState(Integer state)
  {
    if((states.size() < 100) && (state < 10))
    {
      return "\nq" + state + "  - ";
    }

    return "\nq" + state + " - ";
  }

  /**
   * Reconhecer a sentenca de entrada
   *
   * @param sentence sentenca de entrada
   * @return true caso a sentenca de entrada pertenca a linguagem,
   *   false em caso contrario
   */
  public boolean recognize(String sentence)
  {
    String input = sentence + "$";

    System.out.print("Observação: \"$\" representa o fim da sentença");

    Integer state = 0;

    int length = input.length();

    for(int symbol = 0; symbol < length; symbol++)
    {
      System.out.print(formatState(state));

      for(int index = 0; index < length; index++)
      {
        if(index != symbol)
        {
          System.out.print(" " + input.charAt(index) + " ");
        }
        else
        {
          System.out.print("[" + input.charAt(index) + "]");
        }
      }

      state = states.get(state).getTransition(input.charAt(symbol));

      if(state == null)
      {
        System.out.println(" - REJEITA");

        return false;
      }
    }

    if(states.get(state).isAccept())
    {
      System.out.println(" - ACEITA");
    }
    else
    {
      System.out.println(" - REJEITA");
    }

    return states.get(state).isAccept();
  }
}

/*************************************************************************
 * Copyright (C) 2009/2025 - Cristiano Lehrer (cristiano@ybadoo.com.br)  *
 *                  Ybadoo - Solucoes em Software Livre (ybadoo.com.br)  *
 *                                                                       *
 * Permission is granted to copy, distribute and/or modify this document *
 * under the terms of the GNU Free Documentation License, Version 1.3 or *
 * any later version published by the  Free Software Foundation; with no *
 * Invariant Sections,  no Front-Cover Texts, and no Back-Cover Texts. A *
 * A copy of the  license is included in  the section entitled "GNU Free *
 * Documentation License".                                               *
 *                                                                       *
 * Ubuntu 16.10 (GNU/Linux 4.8.0-39-generic)                             *
 * OpenJDK Version "1.8.0_121"                                           *
 * OpenJDK 64-Bit Server VM (build 25.121-b13, mixed mode)               *
 *************************************************************************/

package com.ybadoo.tutoriais.lfa.tutorial02.exercicio03;

import java.util.Scanner;

/**
 * Testar o Automato Finito Deterministico (AFD)
 */
public class Application
{
  /**
   * Constructor
   */
  private Application()
  {

  }

  /**
   * Metodo principal da linguagem de programacao Java
   *
   * @param args argumentos da linha de comando (nao utilizado)
   */
  public static void main(String[] args)
  {
    Scanner scanner = new Scanner(System.in);

    System.out.print("Analise a sentença: ");
    String sentence = scanner.nextLine().trim();

    scanner.close();

    if(sentence.indexOf("$") >= 0)
    {
      System.out.println("A sentença \"" + sentence + "\" é inválida");

      return;
    }

    DeterministicFiniteAutomaton afd = new DeterministicFiniteAutomaton();

    afd.recognize(sentence);
  }
}

/*************************************************************************
 * Copyright (C) 2009/2025 - Cristiano Lehrer (cristiano@ybadoo.com.br)  *
 *                  Ybadoo - Solucoes em Software Livre (ybadoo.com.br)  *
 *                                                                       *
 * Permission is granted to copy, distribute and/or modify this document *
 * under the terms of the GNU Free Documentation License, Version 1.3 or *
 * any later version published by the  Free Software Foundation; with no *
 * Invariant Sections,  no Front-Cover Texts, and no Back-Cover Texts. A *
 * A copy of the  license is included in  the section entitled "GNU Free *
 * Documentation License".                                               *
 *                                                                       *
 * Ubuntu 16.10 (GNU/Linux 4.8.0-39-generic)                             *
 * g++ (Ubuntu 6.2.0-5ubuntu12) 6.2.0 20161005                           *
 *************************************************************************/

#ifndef STATE_HPP_
#define STATE_HPP_

#include <map>

/**
 * Estado do Automato Finito Deterministico
 */
class State
{
  public:

  /**
   * Constructor
   *
   * @param accept estado eh de aceitacao
   */
  State(const bool accept);

  /**
   * Destructor
   */
  virtual ~State();

  /**
   * Retornar se o estado eh de aceitacao
   *
   * @return true (1) se o estado eh de aceitacao,
   *   false (0) em caso contrario
   */
  bool isAccept() const;

  /**
   * Adicionar uma transicao de estado
   *
   * @param symbol simbolo corrente
   * @param state novo estado
   */
  void addTransition(char symbol, int state);

  /**
   * Retornar o novo estado
   *
   * @param symbol simbolo corrente
   * @return novo estado
   */
  int getTransition(char symbol) const;

  private:

  /**
   * Estado eh de aceitacao
   */
  bool accept;

  /**
   * Transicao de estados
   */
  std::map<char, int>* transitions;
};

#endif

/*************************************************************************
 * Copyright (C) 2009/2025 - Cristiano Lehrer (cristiano@ybadoo.com.br)  *
 *                  Ybadoo - Solucoes em Software Livre (ybadoo.com.br)  *
 *                                                                       *
 * Permission is granted to copy, distribute and/or modify this document *
 * under the terms of the GNU Free Documentation License, Version 1.3 or *
 * any later version published by the  Free Software Foundation; with no *
 * Invariant Sections,  no Front-Cover Texts, and no Back-Cover Texts. A *
 * A copy of the  license is included in  the section entitled "GNU Free *
 * Documentation License".                                               *
 *                                                                       *
 * Ubuntu 16.10 (GNU/Linux 4.8.0-39-generic)                             *
 * g++ (Ubuntu 6.2.0-5ubuntu12) 6.2.0 20161005                           *
 *************************************************************************/

#include <map>

#include "State.hpp"

/**
 * Constructor
 *
 * @param accept estado eh de aceitacao
 */
State::State(const bool accept)
{
  State::accept = accept;

  transitions = new std::map<char, int>();
}

/**
 * Destructor
 */
State::~State()
{
  transitions->clear();

  delete transitions;
}

/**
 * Retornar se o estado eh de aceitacao
 *
 * @return true (1) se o estado eh de aceitacao,
 *   false (0) em caso contrario
 */
bool State::isAccept() const
{
  return accept;
}

/**
 * Adicionar uma transicao de estado
 *
 * @param symbol simbolo corrente
 * @param state novo estado
 */
void State::addTransition(char symbol, int state)
{
  transitions->insert(std::pair<char, int>(symbol, state));
}

/**
 * Retornar o novo estado
 *
 * @param symbol simbolo corrente
 * @return novo estado
 */
int State::getTransition(char symbol) const
{
  if(transitions->find(symbol) != transitions->end())
  {
    return transitions->find(symbol)->second;
  }

  return -1;
}

/*************************************************************************
 * Copyright (C) 2009/2025 - Cristiano Lehrer (cristiano@ybadoo.com.br)  *
 *                  Ybadoo - Solucoes em Software Livre (ybadoo.com.br)  *
 *                                                                       *
 * Permission is granted to copy, distribute and/or modify this document *
 * under the terms of the GNU Free Documentation License, Version 1.3 or *
 * any later version published by the  Free Software Foundation; with no *
 * Invariant Sections,  no Front-Cover Texts, and no Back-Cover Texts. A *
 * A copy of the  license is included in  the section entitled "GNU Free *
 * Documentation License".                                               *
 *                                                                       *
 * Ubuntu 16.10 (GNU/Linux 4.8.0-39-generic)                             *
 * g++ (Ubuntu 6.2.0-5ubuntu12) 6.2.0 20161005                           *
 *************************************************************************/

#ifndef DETERMINISTIC_FINITE_AUTOMATON_HPP_
#define DETERMINISTIC_FINITE_AUTOMATON_HPP_

#include <map>
#include <string>

#include "State.hpp"

/**
 * Automato Finito Deterministico (AFD)
 */
class DeterministicFiniteAutomaton
{
  public:

  /**
   * Constructor
   */
  DeterministicFiniteAutomaton();

  /**
   * Destructor
   */
  virtual ~DeterministicFiniteAutomaton();

  /**
   * Reconhecer a sentenca de entrada
   *
   * @param sentence sentenca de entrada
   * @return true (1) caso a sentenca de entrada pertenca a linguagem,
   *   false (0) em caso contrario
   */
  bool recognize(std::string sentence);

  private:

  /**
   * Estados do Automato Finito Deterministico (AFD)
   */
  std::map<int, State*>* states;

  /**
   * Formatar o estado para impressao
   *
   * @param state estado
   * @return estado formatado para impressao
   */
  std::string formatState(int state);
};

#endif

/*************************************************************************
 * Copyright (C) 2009/2025 - Cristiano Lehrer (cristiano@ybadoo.com.br)  *
 *                  Ybadoo - Solucoes em Software Livre (ybadoo.com.br)  *
 *                                                                       *
 * Permission is granted to copy, distribute and/or modify this document *
 * under the terms of the GNU Free Documentation License, Version 1.3 or *
 * any later version published by the  Free Software Foundation; with no *
 * Invariant Sections,  no Front-Cover Texts, and no Back-Cover Texts. A *
 * A copy of the  license is included in  the section entitled "GNU Free *
 * Documentation License".                                               *
 *                                                                       *
 * Ubuntu 16.10 (GNU/Linux 4.8.0-39-generic)                             *
 * g++ (Ubuntu 6.2.0-5ubuntu12) 6.2.0 20161005                           *
 *************************************************************************/

#include <iostream>
#include <map>
#include <sstream>
#include <string>

#include "DeterministicFiniteAutomaton.hpp"

/**
 * Constructor
 */
DeterministicFiniteAutomaton::DeterministicFiniteAutomaton()
{
  states = new std::map<int, State*>();

  State* q0 = new State(false);
  q0->addTransition('i', 0);
  q0->addTransition('j', 0);
  q0->addTransition('k', 1);
  states->insert(std::pair<int, State*>(0, q0));

  State* q1 = new State(false);
  q1->addTransition('i', 2);
  q1->addTransition('j', 0);
  q1->addTransition('k', 1);
  states->insert(std::pair<int, State*>(1, q1));

  State* q2 = new State(false);
  q2->addTransition('i', 0);
  q2->addTransition('j', 0);
  q2->addTransition('k', 3);
  states->insert(std::pair<int, State*>(2, q2));

  State* q3 = new State(true);
  q3->addTransition('i', 2);
  q3->addTransition('j', 0);
  q3->addTransition('k', 1);
  q3->addTransition('$', 3);
  states->insert(std::pair<int, State*>(3, q3));
}

/**
 * Destructor
 */
DeterministicFiniteAutomaton::~DeterministicFiniteAutomaton()
{
  while(!states->empty())
  {
    delete states->begin()->second;

    states->erase(states->begin());
  }

  delete states;
}

/**
 * Reconhecer a sentenca de entrada
 *
 * @param sentence sentenca de entrada
 * @return true (1) caso a sentenca de entrada seja reconhecida,
 *   false (0) em caso contrario
 */
bool DeterministicFiniteAutomaton::recognize(std::string sentence)
{
  using namespace std;

  sentence.insert(sentence.end(), '$');

  cout << "Observação: \"$\" representa o fim da sentença";

  int symbol;

  int index;

  int state = 0;

  State* actual;

  int length = sentence.length();

  for(symbol = 0; symbol < length; symbol++)
  {
    cout << formatState(state);

    for(index = 0; index < length; index++)
    {
      if(index != symbol)
      {
        cout << " " << sentence.at(index) << " ";
      }
      else
      {
        cout << "[" << sentence.at(index) << "]";
      }
    }

    actual = states->find(state)->second;

    state = actual->getTransition(sentence.at(symbol));

    if(state == -1)
    {
      cout << " - REJEITA" << endl;

      return false;
    }
  }

  actual = states->find(state)->second;

  if(actual->isAccept())
  {
    cout << " - ACEITA" << endl;
  }
  else
  {
    cout << " - REJEITA" << endl;
  }

  return actual->isAccept();
}

/**
 * Formatar o estado para impressao
 *
 * @param state estado
 * @return estado formatado para impressao
 */
std::string DeterministicFiniteAutomaton::formatState(int state)
{
  using namespace std;

  stringstream buffer;

  buffer << "\nq" << state;

  if((states->size() < 100) && (state < 10))
  {
    buffer << "  - ";
  }
  else
  {
    buffer << " - ";
  }

  return buffer.str();
}

/*************************************************************************
 * Copyright (C) 2009/2025 - Cristiano Lehrer (cristiano@ybadoo.com.br)  *
 *                  Ybadoo - Solucoes em Software Livre (ybadoo.com.br)  *
 *                                                                       *
 * Permission is granted to copy, distribute and/or modify this document *
 * under the terms of the GNU Free Documentation License, Version 1.3 or *
 * any later version published by the  Free Software Foundation; with no *
 * Invariant Sections,  no Front-Cover Texts, and no Back-Cover Texts. A *
 * A copy of the  license is included in  the section entitled "GNU Free *
 * Documentation License".                                               *
 *                                                                       *
 * Ubuntu 16.10 (GNU/Linux 4.8.0-39-generic)                             *
 * g++ (Ubuntu 6.2.0-5ubuntu12) 6.2.0 20161005                           *
 *************************************************************************/

#include <iostream>
#include <string>

#include "DeterministicFiniteAutomaton.hpp"

/**
 * Metodo principal da linguagem de programacao C++
 *
 * @param argc quantidade de argumentos na linha de comando (nao utilizado)
 * @param argv argumentos da linha de comando (nao utilizado)
 */
int main(int argc, char** argv)
{
  using namespace std;

  string sentence;

  cout << "Analise a sentença: ";
  cin >> sentence;

  if(sentence.find("$") != string::npos)
  {
    cout << "A sentença \"" << sentence << "\" é inválida" << endl;

    return 1;
  }

  DeterministicFiniteAutomaton* afd = new DeterministicFiniteAutomaton();

  afd->recognize(sentence);

  delete afd;

  return 0;
}

##########################################################################
 # Copyright (C) 2009/2025 - Cristiano Lehrer (cristiano@ybadoo.com.br)  #
 #                  Ybadoo - Solucoes em Software Livre (ybadoo.com.br)  #
 #                                                                       #
 # Permission is granted to copy, distribute and/or modify this document #
 # under the terms of the GNU Free Documentation License, Version 1.3 or #
 # any later version published by the  Free Software Foundation; with no #
 # Invariant Sections,  no Front-Cover Texts, and no Back-Cover Texts. A #
 # A copy of the  license is included in  the section entitled "GNU Free #
 # Documentation License".                                               #
 #                                                                       #
 # Ubuntu 16.10 (GNU/Linux 4.8.0-39-generic)                             #
 # gcc/g++ (Ubuntu 6.2.0-5ubuntu12) 6.2.0 20161005                       #
 ##########################################################################

g++ -o State.o -c State.cpp

g++ -o DeterministicFiniteAutomaton.o -c DeterministicFiniteAutomaton.cpp

g++ -o Application.o -c Application.cpp

g++ -o application State.o DeterministicFiniteAutomaton.o Application.o

/*************************************************************************
 * Copyright (C) 2009/2025 - Cristiano Lehrer (cristiano@ybadoo.com.br)  *
 *                  Ybadoo - Solucoes em Software Livre (ybadoo.com.br)  *
 *                                                                       *
 * Permission is granted to copy, distribute and/or modify this document *
 * under the terms of the GNU Free Documentation License, Version 1.3 or *
 * any later version published by the  Free Software Foundation; with no *
 * Invariant Sections,  no Front-Cover Texts, and no Back-Cover Texts. A *
 * A copy of the  license is included in  the section entitled "GNU Free *
 * Documentation License".                                               *
 *                                                                       *
 * Ubuntu 16.10 (GNU/Linux 4.8.0-39-generic)                             *
 * gcc (Ubuntu 6.2.0-5ubuntu12) 6.2.0 20161005                           *
 *************************************************************************/

#include <stdio.h>
#include <string.h>

/**
 * Definicao das constantes
 */
#define ACEITA  1
#define REJEITA 0

/**
 * Prototipo das funcoes
 */
void console(int, int);
int q0(int);
int q1(int);
int q2(int);
int q3(int);

/**
 * Sentenca
 */
char sentence[255];

/**
 * Metodo principal da linguagem de programacao C
 *
 * @param argc quantidade de argumentos na linha de comando (nao utilizado)
 * @param argv argumentos da linha de comando (nao utilizado)
 * @return saida para o sistema operacional (padrao 0)
 */
int main(int argc, char** argv)
{
  printf("Analise a sentença: ");
  fgets(sentence, 255, stdin);

  if(strchr(sentence, '$') != 0)
  {
    sentence[strlen(sentence) - 1] = '\0';
    printf("A sentença \"%s\" é inválida\n", sentence);
    return 1;
  }

  sentence[strlen(sentence) - 1] = '$';

  printf("Observação: \"$\" representa o fim da sentença");

  if(q0(0))
  {
    printf(" - ACEITA\n");
  }
  else
  {
    printf(" - REJEITA\n");
  }

  return 0;
}

/**
 * Imprimir a execucao do automato finito deterministico
 *
 * @param state estado corrente
 * @param symbol simbolo corrente
 */
void console(int state, int symbol)
{
  int i;

  int length = strlen(sentence);

  printf("\nq%i - ", state);

  for(i = 0; i < length; i++)
  {
    if(i != symbol)
    {
      printf(" %c ", sentence[i]);
    }
    else
    {
      printf("[%c]", sentence[i]);
    }
  }
}

/**
 * Estado q0 (inicial)
 *
 * @param symbol simbolo corrente
 * @return ACEITA ou REJEITA
 */
int q0(int symbol)
{
  console(0, symbol);

  switch(sentence[symbol++])
  {
    case 'i': return q0(symbol);
    case 'j': return q0(symbol);
    case 'k': return q1(symbol);
    default : return REJEITA;
  }
}

/**
 * Estado q1
 *
 * @param symbol simbolo corrente
 * @return ACEITA ou REJEITA
 */
int q1(int symbol)
{
  console(1, symbol);

  switch(sentence[symbol++])
  {
    case 'i': return q2(symbol);
    case 'j': return q0(symbol);
    case 'k': return q1(symbol);
    default : return REJEITA;
  }
}

/**
 * Estado q2
 *
 * @param symbol simbolo corrente
 * @return ACEITA ou REJEITA
 */
int q2(int symbol)
{
  console(2, symbol);

  switch(sentence[symbol++])
  {
    case 'i': return q0(symbol);
    case 'j': return q0(symbol);
    case 'k': return q3(symbol);
    default : return REJEITA;
  }
}

/**
 * Estado q3 (final)
 *
 * @param symbol simbolo corrente
 * @return ACEITA ou REJEITA
 */
int q3(int symbol)
{
  console(3, symbol);

  switch(sentence[symbol++])
  {
    case 'i': return q2(symbol);
    case 'j': return q0(symbol);
    case 'k': return q1(symbol);
    case '$': return ACEITA;
    default : return REJEITA;
  }
}

##########################################################################
 # Copyright (C) 2009/2025 - Cristiano Lehrer (cristiano@ybadoo.com.br)  #
 #                  Ybadoo - Solucoes em Software Livre (ybadoo.com.br)  #
 #                                                                       #
 # Permission is granted to copy, distribute and/or modify this document #
 # under the terms of the GNU Free Documentation License, Version 1.3 or #
 # any later version published by the  Free Software Foundation; with no #
 # Invariant Sections,  no Front-Cover Texts, and no Back-Cover Texts. A #
 # A copy of the  license is included in  the section entitled "GNU Free #
 # Documentation License".                                               #
 #                                                                       #
 # Ubuntu 16.10 (GNU/Linux 4.8.0-39-generic)                             #
 # gcc/g++ (Ubuntu 6.2.0-5ubuntu12) 6.2.0 20161005                       #
 ##########################################################################

gcc -o DeterministicFiniteAutomaton.o -c DeterministicFiniteAutomaton.c

gcc -o application DeterministicFiniteAutomaton.o

(*************************************************************************
 * Copyright (C) 2009/2025 - Cristiano Lehrer (cristiano@ybadoo.com.br)  *
 *                  Ybadoo - Solucoes em Software Livre (ybadoo.com.br)  *
 *                                                                       *
 * Permission is granted to copy, distribute and/or modify this document *
 * under the terms of the GNU Free Documentation License, Version 1.3 or *
 * any later version published by the  Free Software Foundation; with no *
 * Invariant Sections,  no Front-Cover Texts, and no Back-Cover Texts. A *
 * A copy of the  license is included in  the section entitled "GNU Free *
 * Documentation License".                                               *
 *                                                                       *
 * Ubuntu 16.10 (GNU/Linux 4.8.0-39-generic)                             *
 * FreePascal IDE for Linux for x86-64 (version 2.6.2-8)                 *
 *************************************************************************)

program DeterministicFiniteAutomaton;

(**
 * Definicao das constantes
 *)
const
  ACEITA  = true;
  REJEITA = false;

(**
 * Prototipo das funcoes
 *)
procedure console(state : integer; symbol : integer); forward;
function q0(symbol : integer) : boolean; forward;
function q1(symbol : integer) : boolean; forward;
function q2(symbol : integer) : boolean; forward;
function q3(symbol : integer) : boolean; forward;

var
  (**
   * Sentenca
   *)
  sentence : string;

(**
 * Imprimir a execucao do automato finito deterministico
 *
 * @param state estado corrente
 * @param symbol simbolo corrente
 *)
procedure console(state : integer; symbol : integer);
var i : integer;
begin
  writeln();
  write('q', state, ' - ');

  for i := 1 to ord(sentence[0]) do
  begin
    if i <> symbol then
    begin
      write(' ', sentence[i], ' ');
    end
    else
    begin
      write('[', sentence[i], ']');
    end;
  end;
end;

(**
 * Estado q0 (inicial)
 *
 * @param symbol simbolo corrente
 * @return ACEITA ou REJEITA
 *)
function q0(symbol : integer) : boolean;
begin
  console(0, symbol);

  case sentence[symbol] of
    'i' : q0 := q0(symbol + 1);
    'j' : q0 := q0(symbol + 1);
    'k' : q0 := q1(symbol + 1);
    else  q0 := REJEITA;
  end;
end;

(**
 * Estado q1
 *
 * @param symbol simbolo corrente
 * @return ACEITA ou REJEITA
 *)
function q1(symbol : integer) : boolean;
begin
  console(1, symbol);

  case sentence[symbol] of
    'i' : q1 := q2(symbol + 1);
    'j' : q1 := q0(symbol + 1);
    'k' : q1 := q1(symbol + 1);
    else  q1 := REJEITA;
  end;
end;

(**
 * Estado q2
 *
 * @param symbol simbolo corrente
 * @return ACEITA ou REJEITA
 *)
function q2(symbol : integer) : boolean;
begin
  console(2, symbol);

  case sentence[symbol] of
    'i' : q2 := q0(symbol + 1);
    'j' : q2 := q0(symbol + 1);
    'k' : q2 := q3(symbol + 1);
    else  q2 := REJEITA;
  end;
end;

(**
 * Estado q3 (final)
 *
 * @param symbol simbolo corrente
 * @return ACEITA ou REJEITA
 *)
function q3(symbol : integer) : boolean;
begin
  console(3, symbol);

  case sentence[symbol] of
    'i' : q3 := q2(symbol + 1);
    'j' : q3 := q0(symbol + 1);
    'k' : q3 := q1(symbol + 1);
    '$' : q3 := ACEITA;
    else  q3 := REJEITA;
  end;
end;

(**
 * Metodo principal da linguagem de programacao Pascal
 *)
begin
  write('Analise a sentença: ');
  readln(sentence);

  if pos('$', sentence) <> 0 then
  begin
    writeln('A sentença "', sentence, '" é inválida');
    halt;
  end;

  sentence := sentence + '$';

  write('Observação: "$" representa o fim da sentença');

  if q0(1) then
  begin
    writeln(' - ACEITA');
  end
  else
  begin
    writeln(' - REJEITA');
  end;
end.