I need to design a Turing Machine Simulator in C++ that takes in an input file that goes something like this:
Q:q1,q2,q3,q4
A:0,1
Z:0,1,x
T:q1,0,q2,x,R
T:q1,1,q2,x,R
T:q2,0,q2,0,R
...
S:q1
F:q3,q4
Where Q is states, A is input values, Z is tape alphabet, S is start state, F is accept and reject states.
It needs to handle an input where it takes in the number of inputs, the input strings and accept or reject.
So if it input is:
3
0,#,1,1
1,1
0,1,0
the output would print out the steps and whether it accepts or rejects.
I need to create a TM that performs arithmetic operations, one that performs string operations, and another of my choice.
Any help on how to get started is appreciated.
Try something like this:
#include <iostream>
#include <string.h>
#include <vector>
#include <fstream>
#include <cstdlib>
#include <stdio.h>
#include "tm.h"
using namespace std;
tm::tm(char *fn)
{
current = "";
readFile(fn);
}
void tm::readFile(char *fn)
{
char temp;
string word = "";
ifstream indata;
bool blank = false;
indata.open(fn); //opens the file
if(!indata) //error message if the file is unable to be opened
{
cout << "Could not open the specified file \"" << fn << "\"" << endl;
exit(1);
}
indata >> temp;
while (!indata.eof())
{
if (temp == 'Q')
{
//cout << "Q" << endl;
indata >> temp;
indata >> temp; //skip the :
while (temp != 'A')
{
if (temp != ',') word += temp;
else
{
QQ.push_back(word);
word = "";
}
indata >> temp;
}
QQ.push_back(word);
word = "";
}
else if (temp == 'A')
{
//cout << "A" << endl;
indata >> temp;
indata >> temp; //skip the :
while (temp != 'Z')
{
if (temp != ',') word += temp;
else
{
AA.push_back(word);
word = "";
}
indata >> temp;
}
AA.push_back(word);
word = "";
}
else if (temp == 'Z')
{
//cout << "Z" << endl;
indata >> temp;
indata >> temp; //skip the :
while (temp != 'T')
{
if (temp != ',') word += temp;
else
{
ZZ.push_back(word);
word = "";
}
indata >> temp;
}
ZZ.push_back(word);
word = "";
for (int i = 0; i < (int)ZZ.size(); i++)
if (ZZ[i].compare(" ") == 0)
blank = true;
if (blank == false) //no blanks were found in the tape alphabet
ZZ.push_back(" ");
}
else if (temp == 'T')
{
//cout << "T" << endl;
indata >> temp;
indata >> temp; //skip the :
bool wasComma = false;
vector<string> row;
while (temp != 'T' && temp != 'S')
{
if (wasComma && temp == ',') //the last one was a comma
{
row.push_back(" ");
wasComma = false;
}
else if (temp != ',')
{
word += temp;
wasComma = false;
}
else
{
row.push_back(word);
word = "";
wasComma = true;
}
indata >> temp;
}
row.push_back(word);
TT.push_back(row);
word = "";
}
else if (temp == 'S')
{
//cout << "S" << endl;
indata >> temp;
indata >> temp; //skip the :
while (temp != 'F')
{
if (temp != ',') word += temp;
else
{
SS = word;
word = "";
}
indata >> temp;
}
SS = word;
word = "";
}
else if (temp == 'F')
{
//cout << "F" << endl;
indata >> temp;
indata >> temp; //skip the :
while (!indata.eof())
{
if (temp != ',')
word += temp;
else
{
FF.push_back(word);
word = "";
}
indata >> temp;
}
FF.push_back(word);
word = "";
}
}
indata.close();
readInput();
runAll();
return;
}
void tm::readInput()
{
int num, k;
cin >> num;
string temp;
getline(cin,temp);
getline(cin,temp);
for (int i = 0; i < num; i++) //num is the number of rows of input to the machine
{
vector<string> row;
string word = "";
for(k = 0; k < (int)temp.size(); k++)
{
if (temp[k] != ',')
word += temp[k];
else if ((int)word.size() > 0)
{
row.push_back(word);
word = "";
}
if (k == (int)temp.size() -1 && (int)word.size() > 0)
{
row.push_back(word);
word = "";
}
}
if (k > 0)
input.push_back(row);
else //if there is an empty row of input to the machine
{
vector<string> row;
row.push_back("e");
input.push_back(row);
}
getline(cin,temp);
}
return;
}
void tm::runAll()
{
checkForAlphabetBlanks();
checkTransitions();
checkStart();
checkFinal();
checkDeterministic();
checkAcceptReject();
checkInput();
int currentPosition;
string currentState, currentSymbol;
bool found, first = true;
for (int i = 0; i < (int)input.size(); i++) //for each row of the input
{
if (first != true)
cout << endl;
first = false;
currentPosition = 0;
currentState = SS;
for (int k = 0; k < 1000; k++) //for each character of input, then up to 1000
{
if (k == 0) //the first time
{
if (0 < (int)input[i].size()) //we are not past the right of the tape
currentSymbol = input[i][0];
else
currentSymbol = " ";
cout << "()" << SS << "(";
for (int g = 0; g < (int)input[i].size(); g++)
{
cout << input[i][g];
if (g != (int)input[i].size() - 1) //it is not the last input
cout << ",";
else
cout << ")" << endl;
}
}
if (currentState.compare(FF[0]) == 0) //check if we are accept
{
cout << "ACCEPT" << endl;
break;
}
else if (currentState.compare(FF[1]) == 0) //check if we are reject
{
cout << "REJECT" << endl;
break;
}
found = false;
for (int g = 0; g < (int)TT.size(); g++)
{
if (TT[g][0].compare(currentState) == 0 && TT[g][1].compare(currentSymbol) == 0) //same state and symbol as the transition line
{
found = true;
currentState = TT[g][2];
input[i][currentPosition] = TT[g][3];
if (TT[g][4].compare("R") == 0) currentPosition++;
else currentPosition--;
//check for out of bounds to the left
if (currentPosition < 0) currentPosition = 0;
cout << "(";
for (int t = 0; t < currentPosition; t++)
{
cout << input[i][t];
if (t != currentPosition - 1) cout << ","; //not the last one
}
cout << ")" << currentState << "(";
for (int t = currentPosition; t < (int)input[i].size(); t++)
{
cout << input[i][t];
if (t != (int)input[i].size() - 1) cout << ","; //not the last one
}
cout << ")" << endl;
if (currentPosition < (int)input[i].size()) currentSymbol = input[i][currentPosition]; //not past the right side of the tape
else
{
currentSymbol = " ";
input[i].push_back(" ");
}
break;
}
}
if (found == true) //a transition was found
{
if (currentState.compare(FF[0]) == 0) //check if accept
{
cout << "ACCEPT" << endl;
break;
}
else if (currentState.compare(FF[1]) == 0) //check if reject
{
cout << "REJECT" << endl;
break;
}
}
else
{
currentPosition++;
cout << "(";
for (int t = 0; t < currentPosition; t++)
{
cout << input[i][t];
if (t != currentPosition - 1) cout << ","; //not the last one
}
cout << ")" << FF[1] << "(";
for (int t = currentPosition; t < (int)input[i].size(); t++)
{
cout << input[i][t];
if (t != (int)input[i].size() - 1) cout << ","; //not the last one
}
cout << ")" << endl;
cout << "REJECT" << endl;
break;
}
if (k == 999)
cout << "DID NOT HALT" << endl;
}
}
return;
}
void tm::checkForAlphabetBlanks()
{
for (int i = 0; i < (int)AA.size(); i++)
{
if (AA[i].compare(" ") == 0)
{
cout << "The alphabet has a blank space." << endl;
exit(1);
}
}
return;
}
void tm::checkTransitions()
{
bool state1, state2, character1, character2;
for (int i = 0; i < (int)TT.size(); i++)
{
//check the direction
if (TT[i][4].compare("R") != 0 && TT[i][4].compare("L") != 0)
{
cout << "The only valid directions are R and L." << endl;
exit(1);
}
//check the states
state1 = false; state2 = false;
for (int k = 0; k < (int)QQ.size(); k++)
{
if (TT[i][0].compare(QQ[k]) == 0) state1 = true;
if (TT[i][2].compare(QQ[k]) == 0) state2 = true;
}
if (state1 == false)
{
cout << "The state " << TT[i][0] << " in transition function number " << i << " is not in the list of states." << endl;
exit(1);
}
if (state2 == false)
{
cout << "The state " << TT[i][2] << " in transition function number " << i << " is not in the list of states." << endl;
exit(1);
}
//check the characters
character1 = false; character2 = false;
for (int k = 0; k < (int)ZZ.size(); k++)
{
if (TT[i][1].compare(ZZ[k]) == 0) character1 = true;
if (TT[i][3].compare(ZZ[k]) == 0) character2 = true;
}
if (character1 == false)
{
cout << "The character '" << TT[i][1] << "' in transition function number " << i << " is not in the tape alphabet." << endl;
exit(1);
}
if (character2 == false)
{
cout << "The character '" << TT[i][3] << "' in transition function number " << i << " is not in the tape alphabet." << endl;
exit(1);
}
}
return;
}
void tm::checkStart()
{
bool in = false;
for (int i = 0; i < (int)QQ.size(); i++)
{
if (SS.compare(QQ[i]) == 0) in = true;
}
if (in == false)
{
cout << "The start state " << SS << " is not in the list of states." << endl;
exit(1);
}
}
void tm::checkFinal()
{
if (FF[0].compare(FF[1]) == 0)
{
cout << "The accept and reject states cannot be the same." << endl;
exit(1);
}
bool accept = false, reject = false;
for (int i = 0; i < (int)QQ.size(); i++)
{
if (FF[0].compare(QQ[i]) == 0) accept = true;
if (FF[1].compare(QQ[i]) == 0) reject = true;
}
if (accept == false)
{
cout << "The accept state " << FF[0] << " is not in the list of states." << endl;
exit(1);
}
if (reject == false)
{
cout << "The reject state " << FF[1] << " is not in the list of states." << endl;
exit(1);
}
}
void tm::checkDeterministic()
{
for (int i = 0; i < (int)TT.size(); i++)
for (int k = i+1; k < (int)TT.size(); k++)
if (TT[i][0].compare(TT[k][0]) == 0 && TT[i][1].compare(TT[k][1]) == 0)
{
cout << "The machine cannot proceed deterministically, transitions " << i << " and " << k << " are the same." << endl;
exit(1);
}
}
void tm::checkAcceptReject()
{
for (int i = 0; i < (int)TT.size(); i++)
{
if (TT[i][0].compare(FF[0]) == 0 || TT[i][0].compare(FF[1]) == 0)
{
cout << "The machine cannot transitions from the accept or reject states." << endl;
}
}
}
void tm::checkInput()
{
bool exists;
for (int i = 0; i < (int)input.size(); i++)
{
for (int k = 0; k < (int)input[i].size(); k++)
{
exists = false;
for (int g = 0; g < (int)AA.size(); g++)
{
if (input[i][k].compare(AA[g]) == 0) exists = true;
}
if (exists == false)
{
if (input[i][0].compare("e") != 0) //it is not 'e'
{
cout << "The input character " << input[i][k] << " is not in the input alphabet." << endl;
exit(1);
}
}
}
}
}