Compare value in array

I'm creating a Sudoku game, and according to the rules of Sudoku, there cannot be the same number in any row or column. My question is this: How do I compare a value with an entire row or column in an array?

For example: I have a 9x9 array that looks like this (a '0' indicates an empty space). Say I place the value '8' in the coordinates 'B2'. How would I check with the entire row '2' and the entire column 'B' to make sure that there isn't a value of '8' already there?

A B C D E F G H I
7 2 3 0 0 0 1 5 9
6 0 0 3 0 2 0 0 8
8 0 0 0 1 0 0 0 2
0 7 0 6 5 4 0 2 0
0 0 4 2 0 7 3 0 0
0 5 0 9 3 1 0 4 0
5 0 0 0 7 0 0 0 3
4 0 0 1 0 3 0 0 6
9 3 2 0 0 0 7 1 4

Much appreciated. :)

Last edited on

quirkyusername (792)

you know how for loops work yes? And how to use the equal to operator (==)? If so then I don't see a problem just loop through the row incrementing the column number, then loop through the column incrementing the row number, checking for equality as you go.

brycematheson (33)

How's something like this?

         for (int col = 0; col < 9; col++)
         {
            for (int row = 0; row < 9; row++)
            {
               if (value == sudokuBoard[row][col])
               {
                  cout << "ERROR: Value \'" << value << "\' in square \'" << letter << number << "\' is invalid\n";
                  cout << "\n";
                  getOption(sudokuBoard);
               }
            }
         }

Last edited on

brycematheson (33)

After some tweaking, I've come up with this. Any suggestions?

      {
         int currentColumn = (letter - 65);
         int currentRow = (number - 1);

         for (int i = 0; i < 9; ++i)
         {
            if (sudokuBoard[i][currentColumn] == value)
            {
               cout << "ERROR: Value \'" << value << "\' in square \'" << letter << number << "\' is invalid\n";
               cout << "\n";
               getOption(sudokuBoard);
            }
            else if (sudokuBoard[currentRow][i] == value)
            {
               cout << "ERROR: Value \'" << value << "\' in square \'" << letter << number << "\' is invalid\n";
               cout << "\n";
               getOption(sudokuBoard);
            }
         }

Browni3141 (578)

Remember that all numbers must be the distinct in each 3*3 square.

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Compare value in array