/* Program na vypocitanie rovnice o troch neznamych pomocou Sarrusovho pravidla o determinantoch... aspon myslim ze sa to tak nejako vola ;-)
Spravu o chybach posielajte na moonware@inmail.sk, aj ked ja dufam ze tu ziadne nebudu, a ak aj budu, ze na ne pridem sam :-) */
// verzia 2.1 - moznost zadat do programu nulu
// verzia 2.0.1 - oprava chyby s nezobrazovanim opacneho lomitka
/* verzia 2.0
- upravenie napovedy
- upravenie formatovania vystupu (setw())
- rozdelenie na viacere funkcie
- uprava vzhladu
- pridanie moznosti ulozit vysledok a postup riesenia do textoveho suboru
*/
/*
// verzia 1.5.4.1 - vylepsenie skusky spravnosti
// verzia 1.5.4 - pridanie skusky spravnosti (zadanie sk na otazku "Zelate si vypocitat dalsi priklad?")
// verzia 1.5.3 - zmena helpu (z "vsetky styri" na "styri potrebne"); pridanie moznosti znova zadat predchadzajucu hodnotu
// verzia 1.5.2.1 - oprava zobrazovania nasobenia - znak . sa plietol s desatinnou bodkou. odteraz nasobenie je *
// verzia 1.5.2 - zmena z signed int na float a long double
// verzia 1.5.1 - pridanie volby exit; po zadani zlej hodnoty program nezacina od zaciatku
// verzia 1.5 - zmena pomenovania premennych z obycajnych na array (odstranenie constructora a destructora - uz nepotrebne)
// verzia 1.4 - zmena zobrazovania postupu riesenia, pridanie helpu
// zmena mena z rovnice_o_troch_neznamych na ro3n kvoli zjednoduseniu; prva verzia s tymto menom je 1.4
// verzia 1.3.1 - pridane "rovnica nema riesenie", teda zabranenie spadnutiu programu, ak D0 == 0
// verzia 1.3 - #define VERSION + postup + otazka na konci (zelate si vypocitat dalsi priklad?)
// verzia 1.2 - oprava chyby s deklaraciou globalnych premennych
// verzia 1.1 - zmena z int na signed int + pridanie destructora (a teda aj zmena vacsiny premennych na pointerov s pouzitim new a delete)
*/

#include <iostream>
#include <fstream>
#include <cstdlib>
#include <string>
#include <cstdio>
#include <iomanip>

#define VERSION 2.1;

using namespace std;

char ver[] = "2.1";
long double a [3][4];
char buffer [50];
char save_path [256];
int sirka (3);

class cDeterminant {
	public:
		void postup (long double D0, long double D1, long double D2, long double D3) {
			// hlavny determinant ---------------------------------------------------------------
			cout << "\nPostup riesenia:\n" << endl;
			cout << "    | " << setw(3) << a[0][0] << " " << setw(3) << a[0][1] << " " << setw(3) << a[0][2] << " |" << endl;
			cout << "D = | " << setw(3) << a[1][0] << " " << setw(3) << a[1][1] << " " << setw(3) << a[1][2] << " | = (" << (a[0][0] * a[1][1] * a[2][2]) << ") + (" << (a[1][0] * a[2][1] * a[0][2]) << ") + (" << (a[2][0] * a[0][1] * a[1][2]) << ") - (" << (a[2][0] * a[1][1] * a[0][2]) << ") - (" << (a[0][0] * a[2][1] * a[1][2]) << ") - (" << (a[1][0] * a[0][1] * a[2][2]) << ") = " << D0 << endl;
			cout << "    | " << setw(3) << a[2][0] << " " << setw(3) << a[2][1] << " " << setw(3) << a[2][2] << " |\n" << endl;
			cout << "(D = " << a[0][0] << "*" << a[1][1] << "*" << a[2][2] << " + " << a[1][0] << "*" << a[2][1] << "*" << a[0][2] << " + " << a[2][0] << "*" << a[0][1] << "*" << a[1][2] << " - (" << a[2][0] << "*" << a[1][1] << "*" << a[0][2] << ") - (" << a[0][0] << "*" << a[2][1] << "*" << a[1][2] << ") - (" << a[1][0] << "*" << a[0][1] << "*" << a[2][2] << ") = " << D0 << ")\n" << endl;
			// determinant D1 -------------------------------------------------------------------
			cout << "     | " << setw(3) << a[0][3] << " " << setw(3) << a[0][1] << " " << setw(3) << a[0][2] << " |" << endl;
			cout << "D1 = | " << setw(3) << a[1][3] << " " << setw(3) << a[1][1] << " " << setw(3) << a[1][2] << " | = (" << (a[0][3] * a[1][1] * a[2][2]) << ") + (" << (a[1][3] * a[2][1] * a[0][2]) << ") + (" << (a[2][3] * a[0][1] * a[1][2]) << ") - (" << (a[2][3] * a[1][1] * a[0][2]) << ") - (" << (a[0][3] * a[2][1] * a[1][2]) << ") - (" << (a[1][3] * a[0][1] * a[2][2]) << ") = " << D1 << endl;
			cout << "     | " << setw(3) << a[2][3] << " " << setw(3) << a[2][1] << " " << setw(3) << a[2][2] << " |\n" << endl;
			cout << "(D1 = " << a[0][3] << "*" << a[1][1] << "*" << a[2][2] << " + " << a[1][3] << "*" << a[2][1] << "*" << a[0][2] << " + " << a[2][3] << "*" << a[0][1] << "*" << a[1][2] << " - (" << a[2][3] << "*" << a[1][1] << "*" << a[0][2] << ") - (" << a[0][3] << "*" << a[2][1] << "*" << a[1][2] << ") - (" << a[1][3] << "*" << a[0][1] << "*" << a[2][2] << ") = " << D1 << ")\n" << endl;
			// determinant D2 -------------------------------------------------------------------
			cout << "     | " << setw(3) << a[0][0] << " " << setw(3) << a[0][3] << " " << setw(3) << a[0][2] << " |" << endl;
			cout << "D2 = | " << setw(3) << a[1][0] << " " << setw(3) << a[1][3] << " " << setw(3) << a[1][2] << " | = (" << (a[0][0] * a[1][3] * a[2][2]) << ") + (" << (a[1][0] * a[2][3] * a[0][2]) << ") + (" << (a[2][0] * a[0][3] * a[1][2]) << ") - (" << (a[2][0] * a[1][3] * a[0][2]) << ") - (" << (a[0][0] * a[2][3] * a[1][2]) << ") - (" << (a[1][0] * a[0][3] * a[2][2]) << ") = " << D2 << endl;
			cout << "     | " << setw(3) << a[2][0] << " " << setw(3) << a[2][3] << " " << setw(3) << a[2][2] << " |\n" << endl;
			cout << "(D2 = " << a[0][0] << "*" << a[1][3] << "*" << a[2][2] << " + " << a[1][0] << "*" << a[2][3] << "*" << a[0][2] << " + " << a[2][0] << "*" << a[0][3] << "*" << a[1][2] << " - (" << a[2][0] << "*" << a[1][3] << "*" << a[0][2] << ") - (" << a[0][0] << "*" << a[2][3] << "*" << a[1][2] << ") - (" << a[1][0] << "*" << a[0][3] << "*" << a[2][2] << ") = " << D2 << ")\n" << endl;
			// determinant D3 -------------------------------------------------------------------
			cout << "     | " << setw(3) << a[0][0] << " " << setw(3) << a[0][1] << " " << setw(3) << a[0][3] << " |" << endl;
			cout << "D3 = | " << setw(3) << a[1][0] << " " << setw(3) << a[1][1] << " " << setw(3) << a[1][3] << " | = (" << (a[0][0] * a[1][1] * a[2][3]) << ") + (" << (a[1][0] * a[2][1] * a[0][3]) << ") + (" << (a[2][0] * a[0][1] * a[1][3]) << ") - (" << (a[2][0] * a[1][1] * a[0][3]) << ") - (" << (a[0][0] * a[2][1] * a[1][3]) << ") - (" << (a[1][0] * a[0][1] * a[2][3]) << ") = " << D3 << endl;
			cout << "     | " << setw(3) << a[2][0] << " " << setw(3) << a[2][1] << " " << setw(3) << a[2][3] << " |\n" << endl;
			cout << "(D3 = " << a[0][0] << "*" << a[1][1] << "*" << a[2][3] << " + " << a[1][0] << "*" << a[2][1] << "*" << a[0][3] << " + " << a[2][0] << "*" << a[0][1] << "*" << a[1][3] << " - (" << a[2][0] << "*" << a[1][1] << "*" << a[0][3] << ") - (" << a[0][0] << "*" << a[2][1] << "*" << a[1][3] << ") - (" << a[1][0] << "*" << a[0][1] << "*" << a[2][3] << ") = " << D3 << ")\n" << endl;}
		long double vypocitajD () {
			return ((a[0][0] * a[1][1] * a[2][2]) + (a[1][0] * a[2][1] * a[0][2]) + (a[2][0] * a[0][1] * a[1][2]) - (a[2][0] * a[1][1] * a[0][2]) - (a[0][0] * a[2][1] * a[1][2]) - (a[1][0] * a[0][1] * a[2][2]));}
		long double vypocitajD1 () {
			return ((a[0][3] * a[1][1] * a[2][2]) + (a[1][3] * a[2][1] * a[0][2]) + (a[2][3] * a[0][1] * a[1][2]) - (a[2][3] * a[1][1] * a[0][2]) - (a[0][3] * a[2][1] * a[1][2]) - (a[1][3] * a[0][1] * a[2][2]));}
		long double vypocitajD2 () {
			return ((a[0][0] * a[1][3] * a[2][2]) + (a[1][0] * a[2][3] * a[0][2]) + (a[2][0] * a[0][3] * a[1][2]) - (a[2][0] * a[1][3] * a[0][2]) - (a[0][0] * a[2][3] * a[1][2]) - (a[1][0] * a[0][3] * a[2][2]));}
		long double vypocitajD3 () {
			return ((a[0][0] * a[1][1] * a[2][3]) + (a[1][0] * a[2][1] * a[0][3]) + (a[2][0] * a[0][1] * a[1][3]) - (a[2][0] * a[1][1] * a[0][3]) - (a[0][0] * a[2][1] * a[1][3]) - (a[1][0] * a[0][1] * a[2][3]));}
};

void help () {
	// ------------------------------------------------------------------------------------------------
	cout << endl;
	cout << "*****************************************************************************" << endl;
	cout << "* --------------------------Napoveda programu ro3n------------------------- *" << endl;
	cout << "* Predpokladajme, ze chceme vypocitat sustavu:                              *" << endl;
	cout << "* 5x - y + z = 4                                                            *" << endl;
	cout << "* 2x + y - 3z = 8                                                           *" << endl;
	cout << "* x - 2y + 5z = -7                                                          *" << endl;
	cout << "* -------------------------1. krok - zadanie hodnot------------------------ *" << endl;
	cout << "* Postupne zadavame hodnoty premennych, kde:                                *" << endl;
	cout << "*     a       b      c      d                   e      f       g      h     *" << endl;
	cout << "*    (5)x + (-1)y + (1)z = (4)                 (2)x + (1)y + (-3)z = (8)    *" << endl;
	cout << "*                          i       j      k       l                         *" << endl;
	cout << "*                         (1)x + (-2)y + (5)z = (-7)                        *" << endl;
	cout << "* teda:    a = 5; b = -1; c = 1; d = 4                                      *" << endl;
	cout << "*          e = 2; f = 1; g = -3; h = 8                                      *" << endl;
	cout << "*          i = 1; j = -2; k = 5; l = -7                                     *" << endl;
	cout << "* Kazde zadane cislo odsuhlasime stlacenim klavesy enter (return).          *" << endl;
	cout << "* Ak sa nahodou pomylime, napiseme prev a zadame hodnotu znova.             *" << endl;
	cout << "* Po zadani vsetkych potrebnych hodnot pokracujeme stlacenim klavesy enter. *" << endl;
	cout << "* ---------------------------2. krok - vysledok---------------------------- *" << endl;
	cout << "* Po zadani vsetkych potrebnych informacii sa zobrazi najprv postup.        *" << endl;
	cout << "* Su tu vypocitane styri potrebne determinanty.                             *" << endl;
	cout << "* Nizsie je zobrazeny vysledok - x, y, z.                                   *" << endl;
	cout << "* Mame moznost ulozit riesenie do textoveho suboru.                         *" << endl;
	cout << "* Podla vyberu napiseme A alebo N a stlacime klavesu enter (return).        *" << endl;
	cout << "* Ak sme zvolili moznost ulozit (A), napiseme meno suboru, pripadne cestu.  *" << endl;
	cout << "* Potom mame moznost program ukoncit, alebo vypocitat dalsi priklad.        *" << endl;
	cout << "* Podla vyberu napiseme A alebo N a stlacime klavesu enter (return).        *" << endl;
	cout << "*****************************************************************************" << endl;
	// ------------------------------------------------------------------------------------------------
}

void ro3n_menu () {
	// ------------------------------------------------------------------------------------------------
	cout << "\n**************************************************************************" << endl;
	cout << "*                           ro3n verzia " << setw(5) << ver << "                            *" << endl;
	cout << "* ---------------------------------------------------------------------- *" << endl;
	cout << "* Priklad sustavy rovnic:                                                *" << endl;
	cout << "* ax + by + cz = d                                                       *" << endl;
	cout << "* ex + fy + gz = h                                                       *" << endl;
	cout << "* ix + jy + kz = l                                                       *" << endl;
	cout << "* ---------------------------------------------------------------------- *" << endl;
	cout << "* Napiste help pre viac informacii. Napiste exit pre ukoncenie programu. *" << endl;
	cout << "* Ak sa pomylite a zadate zlu hodnotu, napiste prev a zadajte znova.     *" << endl;
	cout << "**************************************************************************" << endl;
	// ------------------------------------------------------------------------------------------------
}

int ro3n_input () {
	cout << "Zadajte: " << endl;
	// ------------------------------------------------------------------------------------------------
	znova_a:
	cout << "a = "; cin.getline (buffer, 50); 
	if ((buffer[0] == 'h') && (buffer[1] == 'e') && (buffer[2] == 'l') && (buffer[3] == 'p')) 
	{help (); return 1;} 
	else if ((buffer[0] == 'e') && (buffer[1] == 'x') && (buffer[2] == 'i') && (buffer[3] == 't'))
	{cout << "\nDovidenia!" << endl; return 0;}
	else {a[0][0] = atof (buffer); cout << "Zadali ste: " << a[0][0] << endl;}
	// ------------------------------------------------------------------------------------------------
	znova_b:
	cout << "b = "; cin.getline (buffer, 50); 
	if ((buffer[0] == 'h') && (buffer[1] == 'e') && (buffer[2] == 'l') && (buffer[3] == 'p')) 
	{help (); return 1;} 
	else if ((buffer[0] == 'e') && (buffer[1] == 'x') && (buffer[2] == 'i') && (buffer[3] == 't'))
	{cout << "\nDovidenia!" << endl; return 0;}
	else if ((buffer[0] == 'p') && (buffer[1] == 'r') && (buffer[2] == 'e') && (buffer[3] == 'v'))
	{goto znova_a;} else {a[0][1] = atof (buffer); cout << "Zadali ste: " << a[0][1] << endl;}
	// ------------------------------------------------------------------------------------------------
	znova_c:
	cout << "c = "; cin.getline (buffer, 50); 
	if ((buffer[0] == 'h') && (buffer[1] == 'e') && (buffer[2] == 'l') && (buffer[3] == 'p')) 
	{help (); return 1;} 
	else if ((buffer[0] == 'e') && (buffer[1] == 'x') && (buffer[2] == 'i') && (buffer[3] == 't'))
	{cout << "\nDovidenia!" << endl; return 0;}
	else if ((buffer[0] == 'p') && (buffer[1] == 'r') && (buffer[2] == 'e') && (buffer[3] == 'v'))
	{goto znova_b;} else {a[0][2] = atof (buffer); cout << "Zadali ste: " << a[0][2] << endl;}
	// ------------------------------------------------------------------------------------------------
	znova_d:
	cout << "d = "; cin.getline (buffer, 50); 
	if ((buffer[0] == 'h') && (buffer[1] == 'e') && (buffer[2] == 'l') && (buffer[3] == 'p')) 
	{help (); return 1;} 
	else if ((buffer[0] == 'e') && (buffer[1] == 'x') && (buffer[2] == 'i') && (buffer[3] == 't'))
	{cout << "\nDovidenia!" << endl; return 0;}
	else if ((buffer[0] == 'p') && (buffer[1] == 'r') && (buffer[2] == 'e') && (buffer[3] == 'v'))
	{goto znova_c;} else {a[0][3] = atof (buffer); cout << "Zadali ste: " << a[0][3] << endl;}
	// ------------------------------------------------------------------------------------------------
	znova_e:
	cout << "e = "; cin.getline (buffer, 50); 
	if ((buffer[0] == 'h') && (buffer[1] == 'e') && (buffer[2] == 'l') && (buffer[3] == 'p')) 
	{help (); return 1;} 
	else if ((buffer[0] == 'e') && (buffer[1] == 'x') && (buffer[2] == 'i') && (buffer[3] == 't'))
	{cout << "\nDovidenia!" << endl; return 0;}
	else if ((buffer[0] == 'p') && (buffer[1] == 'r') && (buffer[2] == 'e') && (buffer[3] == 'v'))
	{goto znova_d;} else {a[1][0] = atof (buffer); cout << "Zadali ste: " << a[1][0] << endl;}
	// ------------------------------------------------------------------------------------------------
	znova_f:
	cout << "f = "; cin.getline (buffer, 50); 
	if ((buffer[0] == 'h') && (buffer[1] == 'e') && (buffer[2] == 'l') && (buffer[3] == 'p')) 
	{help (); return 1;} 
	else if ((buffer[0] == 'e') && (buffer[1] == 'x') && (buffer[2] == 'i') && (buffer[3] == 't'))
	{cout << "\nDovidenia!" << endl; return 0;}
	else if ((buffer[0] == 'p') && (buffer[1] == 'r') && (buffer[2] == 'e') && (buffer[3] == 'v'))
	{goto znova_e;} else {a[1][1] = atof (buffer); cout << "Zadali ste: " << a[1][1] << endl;}
	// ------------------------------------------------------------------------------------------------
	znova_g:
	cout << "g = "; cin.getline (buffer, 50); 
	if ((buffer[0] == 'h') && (buffer[1] == 'e') && (buffer[2] == 'l') && (buffer[3] == 'p')) 
	{help (); return 1;} 
	else if ((buffer[0] == 'e') && (buffer[1] == 'x') && (buffer[2] == 'i') && (buffer[3] == 't'))
	{cout << "\nDovidenia!" << endl; return 0;}
	else if ((buffer[0] == 'p') && (buffer[1] == 'r') && (buffer[2] == 'e') && (buffer[3] == 'v'))
	{goto znova_f;} else {a[1][2] = atof (buffer); cout << "Zadali ste: " << a[1][2] << endl;}
	// ------------------------------------------------------------------------------------------------
	znova_h:
	cout << "h = "; cin.getline (buffer, 50); 
	if ((buffer[0] == 'h') && (buffer[1] == 'e') && (buffer[2] == 'l') && (buffer[3] == 'p')) 
	{help (); return 1;} 
	else if ((buffer[0] == 'e') && (buffer[1] == 'x') && (buffer[2] == 'i') && (buffer[3] == 't'))
	{cout << "\nDovidenia!" << endl; return 0;}
	else if ((buffer[0] == 'p') && (buffer[1] == 'r') && (buffer[2] == 'e') && (buffer[3] == 'v'))
	{goto znova_g;} else {a[1][3] = atof (buffer); cout << "Zadali ste: " << a[1][3] << endl;}
	// ------------------------------------------------------------------------------------------------
	znova_i:
	cout << "i = "; cin.getline (buffer, 50); 
	if ((buffer[0] == 'h') && (buffer[1] == 'e') && (buffer[2] == 'l') && (buffer[3] == 'p')) 
	{help (); return 1;} 
	else if ((buffer[0] == 'e') && (buffer[1] == 'x') && (buffer[2] == 'i') && (buffer[3] == 't'))
	{cout << "\nDovidenia!" << endl; return 0;}
	else if ((buffer[0] == 'p') && (buffer[1] == 'r') && (buffer[2] == 'e') && (buffer[3] == 'v'))
	{goto znova_h;} else {a[2][0] = atof (buffer); cout << "Zadali ste: " << a[2][0] << endl;}
	// ------------------------------------------------------------------------------------------------
	znova_j:
	cout << "j = "; cin.getline (buffer, 50); 
	if ((buffer[0] == 'h') && (buffer[1] == 'e') && (buffer[2] == 'l') && (buffer[3] == 'p')) 
	{help (); return 1;} 
	else if ((buffer[0] == 'e') && (buffer[1] == 'x') && (buffer[2] == 'i') && (buffer[3] == 't'))
	{cout << "\nDovidenia!" << endl; return 0;}
	else if ((buffer[0] == 'p') && (buffer[1] == 'r') && (buffer[2] == 'e') && (buffer[3] == 'v'))
	{goto znova_i;} else {a[2][1] = atof (buffer); cout << "Zadali ste: " << a[2][1] << endl;}
	// ------------------------------------------------------------------------------------------------
	znova_k:
	cout << "k = "; cin.getline (buffer, 50); 
	if ((buffer[0] == 'h') && (buffer[1] == 'e') && (buffer[2] == 'l') && (buffer[3] == 'p')) 
	{help (); return 1;} 
	else if ((buffer[0] == 'e') && (buffer[1] == 'x') && (buffer[2] == 'i') && (buffer[3] == 't'))
	{cout << "\nDovidenia!" << endl; return 0;}
	else if ((buffer[0] == 'p') && (buffer[1] == 'r') && (buffer[2] == 'e') && (buffer[3] == 'v'))
	{goto znova_j;} else {a[2][2] = atof (buffer); cout << "Zadali ste: " << a[2][2] << endl;}
	// ------------------------------------------------------------------------------------------------
	znova_l:
	cout << "l = "; cin.getline (buffer, 50); 
	if ((buffer[0] == 'h') && (buffer[1] == 'e') && (buffer[2] == 'l') && (buffer[3] == 'p')) 
	{help (); return 1;} 
	else if ((buffer[0] == 'e') && (buffer[1] == 'x') && (buffer[2] == 'i') && (buffer[3] == 't'))
	{cout << "\nDovidenia!" << endl; return 0;}
	else if ((buffer[0] == 'p') && (buffer[1] == 'r') && (buffer[2] == 'e') && (buffer[3] == 'v'))
	{goto znova_k;} else {a[2][3] = atof (buffer); cout << "Zadali ste: " << a[2][3] << endl;}
	// ------------------------------------------------------------------------------------------------
	cout << "********************************************" << endl;
	cout << "* Moznosti:                                *" << endl;
	cout << "* klavesa enter - vypocitat zadany priklad *" << endl;
	cout << "* prev - znova zadat poslednu hodnotu      *" << endl;
	cout << "* help - napoveda                          *" << endl;
	cout << "* exit - ukoncit program                   *" << endl;
	cout << "********************************************" << endl; cout << "> ";
	cin.getline (buffer, 50); 
	if ((buffer[0] == 'h') && (buffer[1] == 'e') && (buffer[2] == 'l') && (buffer[3] == 'p')) 
	{help (); return 1;} 
	if ((buffer[0] == 'e') && (buffer[1] == 'x') && (buffer[2] == 'i') && (buffer[3] == 't'))
	{cout << "\nDovidenia!" << endl; return 0;}
	if ((buffer[0] == 'p') && (buffer[1] == 'r') && (buffer[2] == 'e') && (buffer[3] == 'v'))
	{goto znova_l;}
	// ------------------------------------------------------------------------------------------------
	cout << endl;
	return 2;
}

int ro3n_output_save (long double D0, long double D1, long double D2, long double D3, long double x, long double y, long double z) {
	// ------------------------------------------------------------------------------------------------
	cout << "\nUlozit riesenie do textoveho suboru? [A/N] "; cin.getline (buffer, 50); 
	if ((buffer[0] == 'N') || (buffer[0] == 'n')) {return 0;} 
	else if ((buffer[0] == 'A') || (buffer[0] == 'a')) {
		cout << "************************************************************************" << endl;
		cout << "* Zadajte meno suboru, pripadne kompletnu cestu. Napriklad:            *" << endl;
		cout << "* Ak zadate:                       Subor priklad.txt bude umiestneny:  *" << endl;
		cout << "* priklad.txt                      do aktualneho priecinka             *" << endl;
		cout << "* C:\\priklad.txt                   na disk C: (Windows)                *" << endl;
		cout << "* /home/uzivatel/priklad.txt       do domovskeho priecinka (Linux)     *" << endl;
		cout << "* /Users/uzivatel/priklad.txt      do domovskeho priecinka (Mac OS X)  *" << endl;
		cout << "************************************************************************" << endl;
		cout << "> "; cin.getline (save_path, 256); ofstream sfile (save_path);
		if (sfile.is_open()) {
			cout << "Subor uspesne vytvoreny." << endl;
			sfile << "------------------------------------ro3n------------------------------------" << endl;
			sfile << "\nPriklad:\n" << endl;
			sfile << a[0][0] << "x + " << a[0][1] << "y + " << a[0][2] << "z = " << a[0][3] << endl;
			sfile << a[1][0] << "x + " << a[1][1] << "y + " << a[1][2] << "z = " << a[1][3] << endl;
			sfile << a[2][0] << "x + " << a[2][1] << "y + " << a[2][2] << "z = " << a[2][3] << endl;
			// hlavny determinant ---------------------------------------------------------------
			sfile << "\nPostup riesenia:\n" << endl;
			sfile << "    | " << setw(3) << a[0][0] << " " << setw(3) << a[0][1] << " " << setw(3) << a[0][2] << " |" << endl;
			sfile << "D = | " << setw(3) << a[1][0] << " " << setw(3) << a[1][1] << " " << setw(3) << a[1][2] << " | = (" << (a[0][0] * a[1][1] * a[2][2]) << ") + (" << (a[1][0] * a[2][1] * a[0][2]) << ") + (" << (a[2][0] * a[0][1] * a[1][2]) << ") - (" << (a[2][0] * a[1][1] * a[0][2]) << ") - (" << (a[0][0] * a[2][1] * a[1][2]) << ") - (" << (a[1][0] * a[0][1] * a[2][2]) << ") = " << D0 << endl;
			sfile << "    | " << setw(3) << a[2][0] << " " << setw(3) << a[2][1] << " " << setw(3) << a[2][2] << " |\n" << endl;
			sfile << "(D = " << a[0][0] << "*" << a[1][1] << "*" << a[2][2] << " + " << a[1][0] << "*" << a[2][1] << "*" << a[0][2] << " + " << a[2][0] << "*" << a[0][1] << "*" << a[1][2] << " - (" << a[2][0] << "*" << a[1][1] << "*" << a[0][2] << ") - (" << a[0][0] << "*" << a[2][1] << "*" << a[1][2] << ") - (" << a[1][0] << "*" << a[0][1] << "*" << a[2][2] << ") = " << D0 << ")\n" << endl;
			// determinant D1 -------------------------------------------------------------------
			sfile << "     | " << setw(3) << a[0][3] << " " << setw(3) << a[0][1] << " " << setw(3) << a[0][2] << " |" << endl;
			sfile << "D1 = | " << setw(3) << a[1][3] << " " << setw(3) << a[1][1] << " " << setw(3) << a[1][2] << " | = (" << (a[0][3] * a[1][1] * a[2][2]) << ") + (" << (a[1][3] * a[2][1] * a[0][2]) << ") + (" << (a[2][3] * a[0][1] * a[1][2]) << ") - (" << (a[2][3] * a[1][1] * a[0][2]) << ") - (" << (a[0][3] * a[2][1] * a[1][2]) << ") - (" << (a[1][3] * a[0][1] * a[2][2]) << ") = " << D1 << endl;
			sfile << "     | " << setw(3) << a[2][3] << " " << setw(3) << a[2][1] << " " << setw(3) << a[2][2] << " |\n" << endl;
			sfile << "(D1 = " << a[0][3] << "*" << a[1][1] << "*" << a[2][2] << " + " << a[1][3] << "*" << a[2][1] << "*" << a[0][2] << " + " << a[2][3] << "*" << a[0][1] << "*" << a[1][2] << " - (" << a[2][3] << "*" << a[1][1] << "*" << a[0][2] << ") - (" << a[0][3] << "*" << a[2][1] << "*" << a[1][2] << ") - (" << a[1][3] << "*" << a[0][1] << "*" << a[2][2] << ") = " << D1 << ")\n" << endl;
			// determinant D2 -------------------------------------------------------------------
			sfile << "     | " << setw(3) << a[0][0] << " " << setw(3) << a[0][3] << " " << setw(3) << a[0][2] << " |" << endl;
			sfile << "D2 = | " << setw(3) << a[1][0] << " " << setw(3) << a[1][3] << " " << setw(3) << a[1][2] << " | = (" << (a[0][0] * a[1][3] * a[2][2]) << ") + (" << (a[1][0] * a[2][3] * a[0][2]) << ") + (" << (a[2][0] * a[0][3] * a[1][2]) << ") - (" << (a[2][0] * a[1][3] * a[0][2]) << ") - (" << (a[0][0] * a[2][3] * a[1][2]) << ") - (" << (a[1][0] * a[0][3] * a[2][2]) << ") = " << D2 << endl;
			sfile << "     | " << setw(3) << a[2][0] << " " << setw(3) << a[2][3] << " " << setw(3) << a[2][2] << " |\n" << endl;
			sfile << "(D2 = " << a[0][0] << "*" << a[1][3] << "*" << a[2][2] << " + " << a[1][0] << "*" << a[2][3] << "*" << a[0][2] << " + " << a[2][0] << "*" << a[0][3] << "*" << a[1][2] << " - (" << a[2][0] << "*" << a[1][3] << "*" << a[0][2] << ") - (" << a[0][0] << "*" << a[2][3] << "*" << a[1][2] << ") - (" << a[1][0] << "*" << a[0][3] << "*" << a[2][2] << ") = " << D2 << ")\n" << endl;
			// determinant D3 -------------------------------------------------------------------
			sfile << "     | " << setw(3) << a[0][0] << " " << setw(3) << a[0][1] << " " << setw(3) << a[0][3] << " |" << endl;
			sfile << "D3 = | " << setw(3) << a[1][0] << " " << setw(3) << a[1][1] << " " << setw(3) << a[1][3] << " | = (" << (a[0][0] * a[1][1] * a[2][3]) << ") + (" << (a[1][0] * a[2][1] * a[0][3]) << ") + (" << (a[2][0] * a[0][1] * a[1][3]) << ") - (" << (a[2][0] * a[1][1] * a[0][3]) << ") - (" << (a[0][0] * a[2][1] * a[1][3]) << ") - (" << (a[1][0] * a[0][1] * a[2][3]) << ") = " << D3 << endl;
			sfile << "     | " << setw(3) << a[2][0] << " " << setw(3) << a[2][1] << " " << setw(3) << a[2][3] << " |\n" << endl;
			sfile << "(D3 = " << a[0][0] << "*" << a[1][1] << "*" << a[2][3] << " + " << a[1][0] << "*" << a[2][1] << "*" << a[0][3] << " + " << a[2][0] << "*" << a[0][1] << "*" << a[1][3] << " - (" << a[2][0] << "*" << a[1][1] << "*" << a[0][3] << ") - (" << a[0][0] << "*" << a[2][1] << "*" << a[1][3] << ") - (" << a[1][0] << "*" << a[0][1] << "*" << a[2][3] << ") = " << D3 << ")\n" << endl;
			// ------------------------------------------------------------------------------------------------
			if (D0 == 0) {sfile << "\nSustava rovnic nema riesenie." << endl;} else {
				sfile << "\nx = D1 : D = " << x << "\ny = D2 : D = " << y << "\nz = D3 : D = " << z << endl;}
			sfile << "\n----------------------------------------------------------------------------" << endl;
			sfile << "Vystup generovany programom ro3n verzia " << ver << endl;
			sfile.close(); cout << "Data uspesne zapisane." << endl;
		} else {cout << "Vyskytol sa problem pri vytvarani/otvarani suboru!" << endl;}
	}
	return 0;
}

void ro3n_skuska (long double D0, long double x, long double y, long double z) {
	// ------------------------------------------------------------------------------------------------
	cout << "\nSkuska spravnosti:" << endl;
	if (D0 != 0) {
		cout << a[0][0] << "*" << x << " + " << a[0][1] << "*" << y << " + " << a[0][2] << "*" << z << " = " << a[0][3] << endl;
		cout << a[1][0] << "*" << x << " + " << a[1][1] << "*" << y << " + " << a[1][2] << "*" << z << " = " << a[1][3] << endl;
		cout << a[2][0] << "*" << x << " + " << a[2][1] << "*" << y << " + " << a[2][2] << "*" << z << " = " << a[2][3] << endl;
		cout << endl;
		cout << ((a[0][0]*x)+(a[0][1]*y)+(a[0][2]*z)) << " = " << a[0][3] << endl;
		cout << ((a[1][0]*x)+(a[1][1]*y)+(a[1][2]*z)) << " = " << a[1][3] << endl;
		cout << ((a[2][0]*x)+(a[2][1]*y)+(a[2][2]*z)) << " = " << a[2][3] << endl;}
	else {cout << "Sustava rovnic nema riesenie." << endl;};
	// ------------------------------------------------------------------------------------------------
}

int main () {
	znova:
	ro3n_menu ();
	zadajte:
	int input_result = 5; input_result = ro3n_input ();
	if (input_result == 0) {return 0;}; if (input_result == 1) {goto zadajte;};
	// ------------------------------------------------------------------------------------------------
	cDeterminant determinant;
	long double D0 = determinant.vypocitajD ();
	long double D1 = determinant.vypocitajD1 ();
	long double D2 = determinant.vypocitajD2 ();
	long double D3 = determinant.vypocitajD3 ();
	determinant.postup (D0, D1, D2, D3);
	long double x, y, z;
	if (D0 == 0) {cout << "\nSustava rovnic nema riesenie." << endl;} else {
		x = D1 / D0; y = D2 / D0; z = D3 / D0;
		cout << "\nx = D1 : D = " << x << "\ny = D2 : D = " << y << "\nz = D3 : D = " << z << endl;}
	// ------------------------------------------------------------------------------------------------
	ro3n_output_save (D0, D1, D2, D3, x, y, z);
	// ------------------------------------------------------------------------------------------------
	vypocitat_dalsi_priklad_a_n:
	cout << "\nZelate si vypocitat dalsi priklad? [A/N] "; cin.getline (buffer, 50); 
	if ((buffer[0] == 'A') || (buffer[0] == 'a')) {goto znova;} 
	else if ((buffer[0] == 'N') || (buffer[0] == 'n')) {cout << "\nDovidenia!" << endl;} 
	else if ((buffer[0] == 's') && (buffer[1] == 'k')) 
		{ro3n_skuska (D0, x, y, z); goto vypocitat_dalsi_priklad_a_n;}
	else {goto vypocitat_dalsi_priklad_a_n;};
	return 0;
}