Data commit

Task/Langtons-ant/C-sharp/langtons-ant.cs

@@ -0,0 +1,93 @@
+using System;
+
+namespace LangtonAnt
+{
+    public struct Point
+    {
+        public int X;
+        public int Y;
+
+        public Point(int x, int y)
+        {
+            X = x;
+            Y = y;
+        }
+    }
+
+    enum Direction
+    {
+        North, East, West, South
+    }
+
+    public class Langton
+    {
+        public readonly bool [,] IsBlack;
+        private Point _origin;
+        private Point _antPosition = new Point(0, 0);
+        public bool OutOfBounds { get; set;}
+
+        // I don't see any mention of what direction the ant is supposed to start out in
+        private Direction _antDirection = Direction.East;
+
+        private readonly Direction[] _leftTurn = new[] { Direction.West, Direction.North, Direction.South, Direction.East };
+        private readonly Direction[] _rightTurn = new[] { Direction.East, Direction.South, Direction.North, Direction.West };
+        private readonly int[] _xInc = new[] { 0, 1,-1, 0};
+        private readonly int[] _yInc = new[] {-1, 0, 0, 1};
+
+        public Langton(int width, int height, Point origin)
+        {
+            _origin = origin;
+            IsBlack = new bool[width, height];
+            OutOfBounds = false;
+        }
+
+        public Langton(int width, int height) : this(width, height, new Point(width / 2, height / 2)) {}
+
+        private void MoveAnt()
+        {
+            _antPosition.X += _xInc[(int)_antDirection];
+            _antPosition.Y += _yInc[(int)_antDirection];
+        }
+
+        public Point Step()
+        {
+            if (OutOfBounds)
+            {
+                throw new InvalidOperationException("Trying to step after ant is out of bounds");
+            }
+            Point ptCur = new Point(_antPosition.X + _origin.X, _antPosition.Y + _origin.Y);
+            bool leftTurn = IsBlack[ptCur.X, ptCur.Y];
+            int iDirection = (int) _antDirection;
+            _antDirection = leftTurn ? _leftTurn[iDirection] : _rightTurn[iDirection];
+            IsBlack[ptCur.X, ptCur.Y] = !IsBlack[ptCur.X, ptCur.Y];
+            MoveAnt();
+            ptCur = new Point(_antPosition.X + _origin.X, _antPosition.Y + _origin.Y);
+            OutOfBounds =
+                ptCur.X < 0 ||
+                ptCur.X >= IsBlack.GetUpperBound(0) ||
+                ptCur.Y < 0 ||
+                ptCur.Y >= IsBlack.GetUpperBound(1);
+            return _antPosition;
+        }
+    }
+    class Program
+    {
+        static void Main()
+        {
+            Langton ant = new Langton(100, 100);
+
+            while (!ant.OutOfBounds) ant.Step();
+
+            for (int iRow = 0; iRow < 100; iRow++)
+            {
+                for (int iCol = 0; iCol < 100; iCol++)
+                {
+                    Console.Write(ant.IsBlack[iCol, iRow] ? "#" : " ");
+                }
+                Console.WriteLine();
+            }
+
+            Console.ReadKey();
+        }
+    }
+}