Can't execute a while loop from a different function properly.

[Neuling]

I can't execute the while loop in stateOne() line 116 properly, if i execute the function from stateTwo() line 256.

The idea behind the code is to simulate a turing machine. The quadruppels are
<S1, 1, move right, S1>
<S1, 0, write 1, S2>
<S2, 1, move left, S2>
<S2, 1, move right, S1>

so the machine should halt when it reads 5 times in a row a '1'. i think it simulates the function f(x) = x + 5 but im not sure if thats the right mathematical translation.

can you help why whe the programm gets "stuck" if stateTwo function calls stateOne function?

// TuringMachine.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"

////////////////////////////////////////////////////TURING MACHINE///////////////////////////////////////////////////////////

//std libraries
#include <iostream>
#include <cstdlib>
#include <ctime>

//using namespace
using namespace std;

/*
//my files
#include "stateOne.cpp"
#include "stateTwo.cpp"


//my headers
#include "definitions.h"
#include "stateOne.h"
#include "stateTwo.h"
*/


//DEFINITIONS
#define READ cout << "\nMACHINE IS IN STATE " << state <<"! On place " << position << " the machine reads a " << tape[position] << ".";
#define PLACE cout << "\nPosition = " << position;
#define STEPS ;

//constants
const char HALT[] = "\n\n\t\t\t\tThe Turing Machine halts! Press any key for exit.";
const char LEFTEND[] = "\nThats the very end of the tape. The TM can't move left to place -1!";
const char RIGHTEND[] = "\nThats the very end of the tape. The TM can't move right to place 100!";
const char CONFINAL[] = "\n\t\t\t\tThe last 5 readings were a '1'.";									//condition when the machine is finished

//functions
//
//

int main()
{
	//variables
	int tape[100];
	int i = 0, n = 0;
	int START;
	char exit;

	//functions
	int stateOne(int tape[], int position);
	int stateTwo(int tape[], int position);

	srand(time(NULL));

	cout << "\n\t\t\t\tCreate a random Turing Machine tape with length 100:\n";

	for(n = 0; n <= 99; n++)												//fill array with random integers from 0 to 1.
	{
		i = rand() % 2;
		tape[n] = i;
		cout << tape[n];
	}

	for (n = 0; n <= 2; n++)												//3 trys to find a nice place to start.
	{
		cout << "\n\nOn what tape number should the TM start? (0-99)\n";
		cin >> START;

		while (START > 99 | START < 0)
		{
			cout << "\nThe entered number is either to big or to small. Please enter a number between 0 and 99.";
			cin >> START;
		}

		cout << "\nPlace " << START << " is a " << tape[START] << "\n";
	}

	cout << "\nMachine starts in S1.";

	stateOne(tape, START);													//here we go!!!

	cin >> exit;

	return 0;
}

//STATE 1
//
//
int stateOne(int tape[], int position)
{
	//vars
	int conFive = 0;
	int state = 1;

	//functions
	int stateTwo(int tape[], int position);

	while ((tape[position] == 1 | tape[position] == 0) && (position >= 0 || position <= 99))					//while reading 1 or 0 and array values are in scope...
	{

		//Dieser Code macht deutlich warum sich zweiwertige Variablen nicht selbst durch Ausschliessung bedingen. Obwohl der Ausdruck nur die Werte 1 und 0 bearbeitet, sagt
		//die Funktion <while (tape[position] == 1) ...>,  obwohl logisch äquivalent zu <while (tape[position] != 0) ...>, nicht das Gleiche aus!
		//Im ersten Fall läuft die Schleife nur 1x, weil die Bedingung immer wahr. Im Zweiten aber solange sie ungleich 0 ist. Schleifen sollten nicht POSITIVE Bedingungen erwarten!

		/*while (tape[position] == 1)
		{
		cout << "\nMACHINE IS IN STATE 1! On place " << position << " the machine reads a " << tape[position] << ".";
		position++;
		cout << "\nCOMMAND => move to place " << position << " and stay in S1.";
		}*/
				
		while (tape[position] != 0 && position <= 99)															//and while the TM is reading 1 ...
		{		
			//cout << "\nMACHINE IS IN STATE 1! On place " << position << " the machine reads a " << tape[position] << ".";
			READ;
			cout << "\n\t=> COMMAND: move to place " << position + 1 << " and stay in State " << state << ".";
			position++;																							//move right
			conFive++;																							//increment final halt condition

			if (position == 99 || position > 99)																//if the tape ends...
			{	
				PLACE;
				cout << RIGHTEND;
				cout << HALT;
				return 0;
				break;
			}

			if (conFive == 5)																					//or if final halt condition is true
			{
				cout << CONFINAL;
				cout << HALT;
				return 0;
				break;
			}

			break;
		}

		while (tape[position] != 1)			 																	//or while the TM is readin 0s...
		{
			if (position > 0)																					//and position is not 0
			{
				READ;
				cout << "\n\t=> COMMAND: replace place " << position << " with 1, move to place " << position - 1 << " and move to S2.";
				tape[position] = 1;																				//overwrite  the 0 with a 1
				position--;																						//move left
				stateTwo(tape, position);																		//and move to state 2.
				break;
			}
			else if (position == 0 && tape[position] == 1)														//else, if the very first number is a 1
			{	
				while (tape[position] != 0 && position <= 99)													//start to repeat again final halt condition (=read 5x 1 in a row)
				{
					READ;
					cout << "\n\t=> COMMAND: move to place " << position + 1 << " and stay in S1.";
					position++;																					//move right
					conFive++;																					//increment final halt condition

					if (position == 99 || position > 99)														//but when the tape ends
					{	
						PLACE;
						cout << RIGHTEND;																		
						cout << HALT;																			//the TM halts.
						break;
						return 0;
					}

					if (conFive == 5)																			//or the final halt condition is true
					{
						cout << CONFINAL;
						cout << HALT;																			//and the TM halts.
						break;
						return 0;
					}

					break;
				}
			}
			else																								//if all conditions above are not true, then we read in position 0 a 0
			{
				PLACE;
				cout << LEFTEND;
				cout << HALT;																					//and the TM halts. (because it can't move right under such conditions)
				break;
				return 0;
			}

		}
		//break;
		return 0;
	}
	return 0;
}

//STATE 2
//
//
int stateTwo(int tape[], int position)
{
	//var
	int conFive = 0;
	int state = 2;

	//functions
	int stateOne(int tape[], int position);

	while ((tape[position] == 1 | tape[position] == 0) && (position >= 0 || position <= 99))		//while reading 1 or 0 and array values are in scope...
	{
		while (tape[position] != 0 && position <= 99)												//while reading 1
		{
			READ;
			cout << "\n\t=> COMMAND: move to place " << position - 1 << " and stay in S2.";			//move left and stay in state 2
			position--;																				
			conFive++;																				//increment final halt condition

			if (position < 0)																		//if the TM reads a number below 0
			{
				//cout << "\nMACHINE IS IN STATE 2! On place " << position << " the machine reads a " << tape[position] << ".";
				PLACE;
				cout << LEFTEND;
				cout << HALT;																		//it halts
				break;
				return 0;
			}

			if (position == 0 && tape[position] == 0)												//if position 0 is a zero (and the TM is in state 2)
			{
				PLACE;
				cout << LEFTEND;
				cout << HALT;																		//it halts
				break;
				return 0;
			}

			if (conFive == 5)																		//if final halt condition is true
			{
				cout << CONFINAL;
				cout << HALT;																		//halt														
				break;
				return 0;
			}
			//break;
		}

		while (tape[position] != 1 && position <= 99)												//while reading 0s
		{
			//cout << "\nMACHINE IS IN STATE 2! On place " << position << " the machine reads a " << tape[position] << ".";
			READ;
			cout << "\n\t=> COMMAND: move to place " << position + 1 << " and move to S1.";			//move right and go to state 1
			position++;
			stateOne(tape, position);																//go to state 1 
			/*
			HERE IS THE PROBLEM! after compiling and executing the code, going to state 1 doesn't behave as it has to.
			it writes only 1 line and the program "stops".
			*/
			break;
		}
		return 0;
	}
	return 0;
}

[SakurasouBusters]

What is your expected output?
What is your broken output?

[Neuling]

i think i fixed it! the break; in line 141 caused the problems.
and i added a new function (besides other adjustments) so i can leave the programm cleanly.


if you want your own turing machine, here is the whole code: (still a little buggy in the prediction)

// TuringMachine.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"

////////////////////////////////////////////////////TURING MACHINE///////////////////////////////////////////////////////////

//std libraries
#include <iostream>
#include <cstdlib>
#include <ctime>

//using namespace
using namespace std;

/*
//my files
#include "stateOne.cpp"
#include "stateTwo.cpp"


//my headers
#include "definitions.h"
#include "stateOne.h"
#include "stateTwo.h"
*/


//DEFINITIONS
#define READ cout << "\nMACHINE IS IN STATE " << state <<"! On place " << position << " the machine reads " << tape[position] << ".";
#define PLACE cout << "\nPosition = " << position;
#define STEPS ;

//constants
const char HALT[] = "\n\n\t\t\t\tThe Turing Machine halts! Press any key for exit.";
const char LEFTEND[] = "\nThats the very end of the tape. The TM can't move left to place -1!";
const char RIGHTEND[] = "\nThats the very end of the tape. The TM can't move right to place 100!";
const char CONFINAL[] = "\n\n\n\t\t\t\tThe last 5 readings were '1'. AMAZING!!!"; //condition when the machine is finished

//functions
//
//

int main()
{
	//variables
	int tape[100];
	int i = 0, n = 0;
	int START;

	//functions
	int stateOne(int tape[], int position);
	int stateTwo(int tape[], int position);
	int halt(int condition);

	srand(time(NULL));

	cout << "\n\t\t\t\tCreate a random Turing Machine tape with length 100:\n";

	for(n = 0; n <= 99; n++) //fill array with random integers from 0 to 1.
	{
		i = rand() % 2;
		tape[n] = i;
		cout << tape[n];
	}

	for (n = 0; n <= 2; n++) //3 trys to find a nice spot to start.
	{
		cout << "\n\nOn what tape number should the TM start? (0-99)\n";
		cin >> START;

		while (START > 99 | START < 0)
		{
			cout << "\nThe entered number is either to big or to small. Please enter a number between 0 and 99.\n";
			cin >> START;
		}
		
		cout << "\nPositon " << START << " is a " << tape[START];

		if (START - 5 <= 94)
		{
			cout <<	". The next 5 positions are: " << tape[START + 1] << " "
				<< tape[START + 2] << " " << tape[START + 3] << " "
				<< tape[START + 4] << " " << tape[START + 5] << " ";
		} 

	}

	cout << "\nMachine starts in S1.";

	stateOne(tape, START); //here we go!!! FUN! FuN! fUn!

	return 0;
}

//STATE 1
//
//
int stateOne(int tape[], int position)
{
	//vars
	int conFive = 0;
	int state = 1;

	//functions
	int stateTwo(int tape[], int position);
	int halt(int condition);

	while ((tape[position] == 1 | tape[position] == 0) && (position >= 0 || position <= 99)) //while the machine is reading 1s or 0s in S1 and array values are in scope...
	{

		//Dieser Code macht deutlich warum sich zweiwertige Variablen nicht selbst durch Ausschliessung bedingen. Obwohl der Ausdruck nur die Werte 1 und 0 bearbeitet, sagt
		//die Funktion <while (tape[position] == 1) ...>,  obwohl logisch äquivalent zu <while (tape[position] != 0) ...>, nicht das Gleiche aus!
		//Im ersten Fall läuft die Schleife nur 1x, weil die Bedingung immer wahr. Im Zweiten aber solange sie ungleich 0 ist. Schleifen sollten nicht POSITIVE Bedingungen erwarten!

		/*while (tape[position] == 1)
		{
		cout << "\nMACHINE IS IN STATE 1! On place " << position << " the machine reads a " << tape[position] << ".";
		position++;
		cout << "\nCOMMAND => move to place " << position << " and stay in S1.";
		}*/
				
		while (tape[position] != 0 && position <= 99) //while the machine is reading 1s in S1
		{		
			//cout << "\nMACHINE IS IN STATE 1! On place " << position << " the machine reads a " << tape[position] << ".";
			READ;
			cout << "\n\t=> COMMAND: move to place " << position + 1 << " and stay in state " << state;
			position++;	//move one position to the right
			conFive++;	//increment final halt condition

			if (position >= 99)	//halt at the right end
			{	
				PLACE;
				halt(position);
				return 0;
				break;
			}

			if (conFive == 5) //halt when machine read 5x '1'
			{
				PLACE;
				halt(conFive);
				return 0;
				break;
			}

		}

		while (tape[position] != 1)	//while reading 0s in S1
		{
			if (position > 0) //and position is not 0
			{
				READ;
				cout << "\n\t=> COMMAND: replace place " << position << " with 1, move to place " << position - 1 << " and move to state " << state + 1;
				tape[position] = 1;																				//overwrite 0 with 1
				position--;																						//move left
				stateTwo(tape, position);																		//and move to state 2.
				break;
			}
			else if (position == 0 && tape[position] == 1) //else, if the machine is reading 1s
			{	
				while (tape[position] != 0 && position <= 99) //while reading 1s in S1
				{
					READ;
					cout << "\n\t=> COMMAND: move to place " << position + 1 << " and stay in state " << state;
					position++;	//move right and stay in S1
					conFive++;	//increment final halt condition

					if (position >= 99)	//halt at the right end
					{	
						PLACE;
						halt(position);	
						break;
						return 0;
					}

					if (conFive == 5) //halt when machine read 5x '1'
					{
						PLACE;
						halt(conFive); 
						break;
						return 0;
					}

					break;
					return 0;
				}
			}
			else //halt at the left end
			{
				PLACE;
				halt(position);	
				break;
				return 0;
			}

		}
		//break;
		return 0;
	}
	return 0;
}

//STATE 2
//
//
int stateTwo(int tape[], int position)
{
	//vars
	int conFive = 0;
	int state = 2;

	//functions
	int stateOne(int tape[], int position);
	int halt(int condition);

	while ((tape[position] == 1 | tape[position] == 0) && (position >= 0 || position <= 99)) //while reading 1 or 0 in S2 and array values are in scope...
	{
		while (tape[position] != 0 && position <= 99) //while reading 1s in S2
		{
			READ;
			cout << "\n\t=> COMMAND: move to place " << position - 1 << " and stay in state " << state;	
			position--;	//move one position to the left, stay in state 2 and																		
			conFive++; //increment final halt condition

			if (position < 0) //halt at left end
			{
				//cout << "\nMACHINE IS IN STATE 2! On place " << position << " the machine reads a " << tape[position] << ".";
				PLACE;
				halt(position);
				break;
				return 0;
			}

			if (position == 0 && tape[position] == 0) //halt at left end
			{
				PLACE;
				halt(position);
				break;
				return 0;
			}

			if (conFive == 5) //halt when machine read 5x '1'
			{
				PLACE;
				halt(conFive);
				break;
				return 0;
			}
			//break;
		}

		while (tape[position] != 1 && position <= 99) //while reading 0s in S2
		{
			//cout << "\nMACHINE IS IN STATE 2! On place " << position << " the machine reads a " << tape[position] << ".";
			READ; 
			cout << "\n\t=> COMMAND: move to place " << position + 1 << " and move to state " << state - 1;  
			position++; //move one position to the right and...
			stateOne(tape, position); //go to state 1 
			break;
		}
		return 0;
	}
	return 0;
}

int halt(int condition)
{
	//vars
	char exit;

	if (condition == 5) //halt when machine read 5x '1'
	{
		cout << CONFINAL;
		cout << HALT;																															
	}

	if (condition <= 0) //halt at left end
	{
		cout << LEFTEND;
		cout << HALT;																		
	}

	if (condition >= 99) //halt at right end
	{
		cout << RIGHTEND;
		cout << HALT;
	}

	cin >> exit;
	return 0;
}