一个打印螺旋数的程序

看到博客园上有人发这个程序的练习，便自己也写了一个。

 1 class ScremNumbers
 2 {
 3     enum Direction { Right, Down, Left, Up }
 4 
 5     [System.Diagnostics.DebuggerDisplay("({X},{Y})")]
 6     struct Point
 7     {
 8         public int X;
 9         public int Y;
10     }
11 
12     public int Count { get; private set; }
13 
14     int[,] numbers;
15     public ScremNumbers(int count)
16     {
17         this.Count = count;
18         numbers = new int[count, count];
19 
20         Process();
21     }
22 
23     void Process()
24     {
25         var point = new Point();
26         var direction = Direction.Right;
27 
28         for (int i = 0; i < Count * Count; i++)
29         {
30             var nextPoint = NextPoint(point, direction);
31             if (this[nextPoint] != 0)
32             {
33                 direction = NextDirection(direction);
34                 nextPoint = NextPoint(point, direction);
35             }
36 
37             this[point] = i + 1;
38             point = nextPoint;
39         }
40     }
41 
42     public void Print()
43     {
44         var maxLength = (Count * Count).ToString().Length + 1;
45 
46         for (int i = 0; i < Count; i++)
47         {
48             for (int j = 0; j < Count; j++)
49             {
50                 Console.Write(numbers[j, i].ToString().PadRight(4));
51             }
52             Console.WriteLine();
53         }
54     }
55 
56     Point NextPoint(Point point, Direction direction)
57     {
58         var nextPoint = point;
59         switch (direction)
60         {
61             case Direction.Right:
62                 nextPoint.X++;
63                 break;
64             case Direction.Down:
65                 nextPoint.Y++;
66                 break;
67             case Direction.Left:
68                 nextPoint.X--;
69                 break;
70             case Direction.Up:
71                 nextPoint.Y--;
72                 break;
73             default:
74                 throw new InvalidOperationException();
75         }
76 
77         return nextPoint;
78     }
79 
80     Direction NextDirection(Direction direction)
81     {
82         return (Direction)(((int)direction + 1) % 4);
83     }
84 
85     private int this[Point index]
86     {
87         get
88         {
89             if (index.X < 0 || index.X >= Count || index.Y < 0 || index.Y >= Count)
90                 return -1;
91 
92             return numbers[index.X, index.Y];
93         }
94 
95         set { numbers[index.X, index.Y] = value; }
96     }
97 }

程序用的算法比较简单，是一种最直接的算法：不停的往前走，碰壁便转弯。总体感觉整体思路还比较清晰，这里记录一下。