sudoku solving in c++ using class [closed] - c++

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This sudoku solving program is getting compiled but getting error "segmentation fault " please help me in solving this problem and clarify why i am getting segmentation error as i have written every thing properlu .thanks in advance
#include<iostream>
#include<math.h>
class sudoku
{
public:
sudoku();
void initializeSudokuGrid();
void printSudokuGrid();
bool solveSudoku();
bool findEmptyGridSlot(int &row, int &col);
bool canPlaceNum(int row, int col, int num);
bool numAlreadyInRow(int row, int num);
bool numAlreadyInCol(int col, int num);
bool numAlreadyInBox(int smallGridRow, int smallGridCol, int num);
int grid[9][9];
};
sudoku::sudoku()
{
for (int i = 0; i < 9; i++)
{
for (int j = 0; j < 9; j++)
{
grid[i][j] = 0;
}
}
std::cout << "\n all the grid locations are initialise to zero";
}
void sudoku::initializeSudokuGrid()
{
char x = 'y';
while (x == 'y')
{
int row, col, var;
std::cout
<< "\n enter the row,column and integer in the box(that is 1-9 numbers \n";
std::cin >> row;
std::cin >> col;
std::cin >> var;
grid[row][col] = var;
std::cout
<< "\n are there any slots that u want to enter the numbers into the boxs enter y else enter n \n";
std::cin >> x;
}
}
void sudoku::printSudokuGrid()
{
std::cout << "\n";
for (int i = 0; i < 9; i++)
{
for (int j = 0; j < 9; j++)
{
std::cout << grid[i][j] << " ";
}
std::cout << "\n";
}
}
bool sudoku::solveSudoku()
{
int row, col;
if (findEmptyGridSlot(row, col))
{
for (int num = 1; num <= 9; num++)
{
if (canPlaceNum(row, col, num))
{
grid[row][col] = num;
if (solveSudoku()) //recursive call
return true;
grid[row][col] = 0;
}
}
return false; //backtrack
}
else
return true; //there are no empty slots
}
bool sudoku::numAlreadyInRow(int row, int num)
{
for (int i = 0; i < 9; i++)
{
if (num != 0 && grid[row][i] == num)
return true;
}
return false;
}
bool sudoku::numAlreadyInCol(int col, int num)
{
for (int i = 0; i < 9; i++)
{
if (num != 0 && grid[i][col] == num)
return true;
}
return false;
}
bool sudoku::canPlaceNum(int row, int col, int num)
{
if (!numAlreadyInRow(row, num))
{
if (!numAlreadyInCol(col, num))
{
int smallGridRow = row - row % 3;
int smallGridCol = col - col % 3;
if (!numAlreadyInBox(smallGridRow, smallGridCol, num))
{
return true;
}
}
}
return false;
}
bool sudoku::numAlreadyInBox(int smallGridRow, int smallGridCol, int num)
{
for (int i = 0; i < 3; i++)
{
for (int j = 0; j < 3; j++)
{
if (grid[i + smallGridRow][j + smallGridCol] == num)
return true;
}
}
return false;
}
bool sudoku::findEmptyGridSlot(int &row, int &col)
{
for (int row = 0; row < 9; row++)
{
for (int col = 0; col < 9; col++)
{
if (grid[row][col] == 0)
return true;
}
}
return false;
}
int main()
{
sudoku s;
s.printSudokuGrid();
s.initializeSudokuGrid();
s.printSudokuGrid();
std::cout << "\n after solving the problem \n";
if (s.solveSudoku())
s.printSudokuGrid();
else
std::cout << "\n solution doesnt exist for this type of solution \n";
return 0;
}

Answer 1

There's a mistake in your findEmptyGridSlot function
bool sudoku::findEmptyGridSlot(int &row, int &col)
{
for(int row=0;row<9;row++)
{
for(int col=0;col<9;col++)
{
...
You're declaring new int variables row and col in the loops, but you probably meant to use the ones passed as parameters.
Remove the int keyword to use the parameters instead of declaring new variables:
for(row=0;row<9;row++)
{
for(col=0;col<9;col++)
{