Method isBoxSafe

C++/Sudoku-Solver.cpp:33–45

to check whether num is valid in that 3*3 matrix grid

    
    // to check whether num is valid in that 3*3 matrix grid 
    bool isBoxSafe(vector<vector<char>>& board, int row1, int col1 , char  num)
    {
         for(int row = 0;row<3;row++)
            {
                for(int col = 0;col<3;col++)
                    {
                         if(board[row1 + row][col1 + col] == num)
                            return true;
                    }
            }
        
        return false;
    }
    
    bool isSafe(vector<vector<char>>& board, int row, int col , char  num)
    {