Java的打印输出练习-画圈打印

Java的打印输出练习-画圈打印

最近复习Java，发现很多有意思的面试题，颇为经典，这些题目也是学习Java的比较有利于思考的练习题。关于Java的打印输出，今天就列举题一：把1、2、3  . . . n画圈打印出来，例如下图：

据说这道题是深圳某家公司的面试题，网上有解。对此题我考虑再三发现除了用二维数组来解答外，实在想不出合适的办法，因为你只能把这些数据放在一个二维数据中，才好控制水平方向和垂直方向的增减，现列举一种答案供参考：

1    package org.j2se;
2    public class SnakePrint {
3        public static int length = 6;
4        public static int value = 1;
5        public static int[][] snake = new int[length][length];
6        public static Direction lastDirection = Direction.Right;
7        public static enum Direction {
8            Right, Down, Left, Up;
9        }
10       public static void initArray() {
11           int hori = 0, ver = 0;
12           for (int c = 0; c < length * length; c++) {
13               snake[hori][ver] = value;
14               lastDirection = findDirection(hori, ver);
15               switch (lastDirection) {
16               case Right:
17                   ver++;
18                   break;
19               case Down:
20                   hori++;
21                   break;
22               case Left:
23                   ver--;
24                   break;
25               case Up:
26                   hori--;
27                   break;
28               default:
29                   System.out.println("error");
30               }
31               value++;
32           }
33       }
34       public static Direction findDirection(int hori, int ver) {
35           Direction direction = lastDirection;
36           switch (direction) {
37           case Right: {
38               if ((ver == length - 1) || (snake[hori][ver + 1] != 0))
39                   direction = Direction.Down;
40               break;
41           }
42           case Down: {
43               if ((hori == length - 1) || (snake[hori + 1][ver] != 0))
44                   direction = Direction.Left;
45               break;
46           }
47           case Left: {
48               if ((ver == 0) || (snake[hori][ver - 1] != 0))
49                   direction = Direction.Up;
50               break;
51           }
52           case Up: {
53               if (snake[hori - 1][ver] != 0)
54                   direction = Direction.Right;
55               break;
56           }
57           }
58           return direction;
59       }
60       public static void main(String[] args) {
61           initArray();
62           for (int i = 0; i < length; i++) {
63               for (int j = 0; j < length; j++) {
64                   System.out.print(snake[i][j] + " ");
65               }
66               System.out.println();
67           }
68       }
69   }