TheExplorer

using System;

public class TheExplorer
{
    public static void Main()
    {
        // input n = diamond width
        int n = int.Parse(Console.ReadLine());

        /*
            In the loop below the last row is n-1 because the counting starts from 0;

            Bacause of the fact that the last row is n-1, then the central row will be n/2.
            For example: n = 5;
                1) if we start counting from 1;
            so five elements will be: 12345. And the Middle element is "3"
            -> center will be n/2 + 1 or 5/2 + 1 -> 2+1 = 3;
                2) if we start counting from 0;
            so five elements will be: 01234. As you can see mid elelemt is "2"
            -> center will be n/2 or 5/2 = 2;
        */

        for (int i = 0; i < n; i++)
        {
            // check is the row counter(i) is first or last row.
            if (i == 0 || i == n - 1)
            {
                string outDiamond = new string('-', n / 2);
                string diamondLine = new string('*', 1);
                Console.WriteLine("{0}{1}{0}", outDiamond, diamondLine);
            }
            // draw the central line
            else if (i == (n/2))
            {
                string diamondLine = new string('*', 1);
                string innerDiamond = new string('-', n - 2);
                Console.WriteLine("{0}{1}{0}", diamondLine, innerDiamond);
            }

            // Above the central line of the diamond
            else if (i < (n/2))
            {
                string outDiamond = new string('-', n / 2 - i);
                string diamondLine = new string('*', 1);
                string innerDiamond = new string('-', 2*(i-1)+1);
                Console.WriteLine("{0}{1}{2}{1}{0}", outDiamond, diamondLine, innerDiamond);
            }
            // Every other case is covered so  this is for the draw
            // bellow the central line.
            else
            {
                string outDiamond = new string('-', Math.Abs(n/2-i));
                string diamondLine = new string('*', 1);
                string innerDiamond = new string('-', Math.Abs(n-2 - 2*(i - n/2)));
                Console.WriteLine("{0}{1}{2}{1}{0}", outDiamond, diamondLine, innerDiamond);
            }
        }
    }
}