/*
 * Unit 6. Loops
 * Exercise 6.14.
 *
 * Write a program that reads a positive integer
 * number N (N < 20) from console and outputs in the
 * console the numbers 1 ... N numbers arranged as a spiral.
 *
 * Author: Pavel Petrov (AN: 9001944)
 *
 */

using System;
using System.Collections.Generic;

class SpiralMatrix
{
    static void Main()
    {
        // The matrix size
        int n = 0;

        int currentValue = 1;
        int pos = -1;           // Direction  1: ascending, -1: descending
        int row = 0, col = 0;   // Current row, col

        // User choice of matrix size
        Console.Write("Enter the matrix size: ");
        bool isInteger = Int32.TryParse(Console.ReadLine(), out n);
        Console.WriteLine();

        if (isInteger)
        {
            int[,] matrix = new int[n, n];      // The matrix
            int maxDirections = (n * 2) - 1;    // Total number of moves
            int size = n;                       // Size of current move
            string[] directions = { "up", "right", "down", "left" };   // Directions (for clarity)



            for (int currentDirection = 1; currentDirection <= maxDirections; currentDirection++)
            {
                if (currentDirection % 2 == 0)
                {
                    size--;     // Decrease size of next move
                }
                else
                {
                    pos *= -1;  // Change direction of move
                }

                // Fill the matrix
                for (int i = 0; i < size; i++)
                {
                    switch (directions[currentDirection % 4])
                    {
                        case "right":
                        case "left":
                            col += pos;
                            matrix[row, col - 1] = currentValue;
                            break;
                        case "down":
                        case "up":
                            row += pos;
                            matrix[row, col - 1] = currentValue;
                            break;
                    }

                    // Next member
                    currentValue++;
                }
            }

            // Print the matrix
            for (int i = 0; i < n; i++)
            {
                Console.WriteLine();
                for (int j = 0; j < n; j++)
                {
                    Console.Write("{0,4}", matrix[i, j]);

                }
                Console.WriteLine();
            }

            Console.WriteLine();
        }
        else
        {
            Console.WriteLine("The matrix size must be a integer number only!!!");
        }
    }
}