SnakeSimple.cs

using System;
using System.Drawing;

namespace SnakePrep
{
    internal class Program
    {
        private static ConsoleKey _direction = ConsoleKey.Escape;
        private static bool _gameOver = false;
        private static Point _current;
        private static Point _previous;
        private static Size _size = new Size(40, 20);
        private static Point _fruit;
        private static int _score;

        private static void Main(string[] args)
        {
            Start();

            while (_gameOver == false)
            {
                Input();
                Logic();
                Draw();
                System.Threading.Thread.Sleep(100);
            }

            Console.Read();
        }

        private static void Logic()
        {
            var next = _current;
            if (_direction == ConsoleKey.UpArrow) { next.Y = next.Y - 1; }
            if (_direction == ConsoleKey.DownArrow) { next.Y = next.Y + 1; }
            if (_direction == ConsoleKey.LeftArrow) { next.X = next.X - 1; }
            if (_direction == ConsoleKey.RightArrow) { next.X = next.X + 1; }
            if (next != _current)
            {
                _previous = _current;
                _current = next;
            }

            if (_current.X == 0
                || _current.X == _size.Width - 1
                || _current.Y == 0
                || _current.Y == _size.Height)
            {
                _gameOver = true;
                Draw();
            }
            if (_current == _fruit)
            {
                _score++;
                _fruit = GetRandomPoint();
            }
        }

        private static void Draw()
        {
            Write(_previous.X, _previous.Y, " ");
            Write(_current.X, _current.Y, "8");
            Write(_fruit.X, _fruit.Y, "q");
            Write(0, 21, "Score: " + _score.ToString().PadRight(5));
        }

        private static void Input()
        {
            if (Console.KeyAvailable)
            {
                var key = Console.ReadKey(true).Key;
                if (key == ConsoleKey.UpArrow
                    || key == ConsoleKey.DownArrow
                    || key == ConsoleKey.LeftArrow
                    || key == ConsoleKey.RightArrow)
                {
                    _direction = key;
                }
            }
        }

        private static void Start()
        {
            Console.CursorVisible = false;
            Console.Clear();

            _current = GetRandomPoint();
            _previous = new Point(10, 9);
            _fruit = GetRandomPoint();

            var line = $"{new string('+', 40)}";

            Write(0, 0, line);
            Write(0, 20, line);

            line = "+" + new string(' ', 38) + "+";

            for (var i = 1; i < 20; i++)
            {
                Write(0, i, line);
            }
        }

        public static void Write(int x, int y, string line)
        {
            Console.SetCursorPosition(x, y);
            Console.WriteLine(line);
        }

        private static readonly Random _random = new Random();

        public static Point GetRandomPoint()
        {
            var point = new Point
            {
                X = _random.Next(1, _size.Width - 2),
                Y = _random.Next(1, _size.Height - 2)
            };
            return point;
        }
    }
}