回形数

package Array;

import java.util.Scanner;


public class RectangleTest {
    //回形数
    /*
    * 从键盘输入一个整数（1~20） ，则以该数字为矩阵的大小，把1,2,3…n*n 的数字按照顺时针螺旋的形式填入其中。
    * */
    enum Direcion{Left,Right,Up,Down};
    public static void main(String[] args) {
        Scanner scanner =new Scanner(System.in);
        int len=scanner.nextInt();
        if(len<1 || len>20) System.out.println("请输入1-20的数字");
        else huixing(len);
    }
    public static void huixing(int num){
        int[][] arr=new int[num][num];
        int row=0,col=0;
        int allnum=1;
        Direcion direction=Direcion.Right;
        while (true){
            if(direction == Direcion.Right){
                if(col < num && arr[row][col] == 0){
                    arr[row][col++]=allnum++;
                }else {
                    direction=Direcion.Down;
                    row++;
                    col--;
//                    allnum--;
                }
            }else if(direction == Direcion.Down){
                if(row < num && arr[row][col] == 0){
                    arr[row++][col]=allnum++;
                }else {
                    direction=Direcion.Left;
                    row--;
                    col--;
//                    allnum--;
                }
            }else if(direction == Direcion.Left){
                if(col >=0 && arr[row][col] == 0){
                    arr[row][col--]=allnum++;
                }else {
                    direction=Direcion.Up;
                    row--;
                    col++;
//                    allnum--;
                }
            }else if(direction == Direcion.Up){
                if(row >=0 && arr[row][col] == 0){
                    arr[row--][col]=allnum++;
                }else {
                    direction=Direcion.Right;
                    row++;
                    col++;
//                    allnum--;
                }
            }

            if(allnum == num*num+1)break;
        };


        for (int i = 0; i < arr.length; i++) {
            for (int j = 0; j < arr[i].length; j++) {
                System.out.print(arr[i][j] + "\t\t");
            }
            System.out.println();
        }
    }
}

　　方案2：

package Array;


public class RectangleTest1 {
    public static void main(String[] args) {
        int n=5;
        int[][] arr = new int[n][n];
        int count=0;
        int MaxX=n-1;//x轴最大值
        int MaxY=n-1;//y轴最大值
        int MinX=0;//x轴最小值
        int MinY=0;//y轴最小值
        while (MinX <= MaxX){
            for (int x = MinX; x <=MaxX ; x++) {
                arr[MinY][x]=++count;
            }
            MinY++;
            for (int y = MinY; y <= MaxY; y++) {
                arr[y][MaxX]=++count;
            }
            MaxX--;
            for (int x = MaxX; x >=MinX ; x--) {
                arr[MaxY][x]=++count;
            }
            MaxY--;
            for (int y = MaxY; y >=MinY ; y--) {
                arr[y][MinX]=++count;
            }
            MinX++;
        }
        for (int i = 0; i < arr.length; i++) {
            for (int j = 0; j < arr[i].length; j++) {
                System.out.print(arr[i][j] + "\t\t");
            }
            System.out.println();
        }
    }
}