Printing an Alternating Pattern to the Console

For this assignment, you will create the pattern of a chess board that
is 8 x 8. Use X and O to represent the squares.

• Create the appropriate nested looping structure to output the characters in an 8 x 8 grid on the screen using Console.Write() or

Console.WriteLine() as appropriate.

• Include a decision structure to ensure that alternate rows start with opposite characters as a real chess board alternates the colors

among rows.


Simple enough, but my first version stuffed everything inside of Main, which I don't care for. So, I wrote a second version that nicely separated the concerns. The problem with that, in my eyes at least, is that it now does exactly twice the amount of work as my initial "naive" version. Does the benefit of separating concerns outweigh the performance hit on an already exponential algorithm?

Also, I don't like this snippet (that exists in both versions of the code).

if (row % 2 == 0)
{
  grid[row, col] = (col % 2 == 0) ? dark : light;
}
else
{
  grid[row, col] = (col % 2 == 0) ? light : dark; 
}

This differs only in the order of the characters, but I'm too close to it at this point to see a better way to clean up the control logic. Advice on it would be appreciated.

Version 1:

public static void Main()
{
    const int gridSize = 8;
    const string dark = "x";
    const string light = "o";

    for (var row = 0; row < gridSize; row++)
    {
        for (var col = 0; col < gridSize; col++)
        {   
            string output;
            if (row % 2 == 0)
            {
                output = (col % 2 == 0) ? dark : light;
            }
            else
            {
                output = (col % 2 == 0) ? light : dark;
            }

            Console.Write(output);  
        }
        Console.WriteLine();
    }
}

Version 2: (ideone here)

```
public static void Main()
{
var grid = CreateGrid(8, 'o', 'x');
PrintGrid(grid);
}

private static void PrintGrid(char[,] grid)
{
for

I like that you have separated the CreateGrid method out in to a reusable method. This is good.

Your logic inside the method is even quite good, despite your concerns about the duplication. There is a trick, though.... use a boolean:

for (var row = 0; row < gridSize; row++)
    {
        bool toggle = row % 2 == 0;
        for (var col = 0; col < gridSize; col++)
        {
            grid[row, col] = toggle ? dark : light;
            toggle = !toggle;
        }
    }

Your print-grid method would likely benefit from some Linq, but what you have is OK.... rather, it is very readable. Linq (or using a StringBuilder) will improve performance by reducing the calls to Write.

StackExchange Code Review Q#86252, answer score: 8