Programma C++ : Sudoku

#include <iostream>

#include <fstream>

class element{

private:

int i, j;

bool is_fixed [9][9];

int start[9][9];

int guess[9][9];

public:

void Next();

void Previus();

bool CheckRow() const;

bool CheckCol() const;

bool CheckSqr() const;

bool Check() const;

void Read(const std::string&);

void Reset();

void PrintStart() const;

void PrintGuess() const;

bool IsFixed() const;

bool IsFirst() const;

bool IsLast() const;

int GetI() const;

int GetJ() const;

int GetStartVal() const;

void Try(int N);

void GuessIs(int N);

void RemoveGuess();

int GetGuess() const;

void Finished() const;

};

void element::Try(int N){

//PrintGuess();

while (IsFixed()){

Next();

}

GuessIs(N);

const bool ch = Check();

if ((ch) && (IsLast())){

Finished();

}

if (ch && (!IsLast())) {

Next();

Try(1);

}

if (!ch){

if (N<9) {

N++;

Try(N);

}

else {

do {

RemoveGuess();

Previus();

} while ((GetGuess()+1)>9);

Try(GetGuess()+1);

}

}

}

void element::GuessIs(int N){

if (IsFixed()) {

std::cerr<<" Error: try to guess a fix \n";

return;

}

guess[i][j] = N;

}

void element::RemoveGuess(){

guess[i][j] = 0;

}

int element::GetGuess() const{

return (guess[i][j]);

}

void element::Finished() const{

PrintGuess();

std::cout<<"Sudoku Solved! \n";

}

void element::Next(){

do {

j = (i+1<9) ? j : j+1;

i = (i+1<9) ? i+1 : 0;

} while ((is_fixed[i][j]) && (!((i==8)&&(j==8))));

if (j>8){

i=8;

j=8;

}

}

void element::Previus(){

if (!((i==0)&&(j==0))) {

do {

j = (i-1>=0) ? j : j-1;

i = (i-1>=0) ? i-1 : 8;

} while ((is_fixed[i][j]) && (!((i==0)&&(j==0))));

}

}

bool element::CheckRow() const{

for (int x=0; x<9; x++){

if ((guess[i][j]==guess[x][j]) && (x!=i) && (guess[i][j]!=0))

return false;

}

return true;

}

bool element::CheckCol() const{

for (int y=0; y<9; y++){

if ((guess[i][j]==guess[i][y]) && (y!=j) && (guess[i][j]!=0))

return false;

}

return true;

}

bool element::CheckSqr() const{

const int sqi = i/3;

const int sqj = j/3;

for (int x=0; x<3; x++){

for (int y=0; y<3; y++){

if ((guess[i][j]==guess[3*sqi+x][3*sqj+y]) && (!

((j==3*sqj+y)&&(i==3*sqi+x))) && (guess[i][j]!=0))

return false;

}

}

return true;

}

bool element::Check() const{

return ((CheckRow()) && (CheckCol()) && (CheckSqr()));

}

bool element::IsFirst() const{

return ((i==0)&&(j==0));

}

bool element::IsLast() const{

return ((i==8) && (j==8));

}

bool element::IsFixed() const{

return (is_fixed[i][j]);

}

int element::GetI() const{

return i;

}

int element::GetJ() const{

return j;

}

int element::GetStartVal() const{

return start[i][j];

}

void element::Reset(){

i = 0;

j = 0;

for (int x=0; x<9; x++){

for (int y=0; y<9; y++){

is_fixed[x][y] = 0;

start[x][y] = 0;

guess[x][y] = 0;

}

}

}

void element::Read(const std::string& filename){

std::ifstream f;

f.open(filename.c_str());

if (!f){

std::cerr<<"File "<<filename<<" not found \n";

return;

}

while (!f.eof()){