java數組練習題，數組順時針螺旋填數.

2維n方陣數組   把1，2，3，...，n*n的數字按照順時針螺旋的形式填入其中。

 

package test;

import java.util.Scanner;

public class TestArray2 {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        System.out.println("請輸入N值：");
        int n = sc.nextInt();
        int up = 0;
        int down = n - 1;
        int left = 0;
        int right = n-1;
        int num = 0;
        int[][] arr = new int[n][n];
        while(down>=up && right>=left){
            for(int i=left;i<=right;i++){
                arr[up][i] = num;
                num++;
            }
            up++;
            for(int i=up;i<=down;i++){
                arr[i][right] = num;
                num++;
            }
            right--;
            for(int i = right;i>=left;i--){
                arr[down][i] = num;
                num++;
            }
            down--;
            for(int i=down;i>=up;i--){
                arr[i][left] = num;
                num++;
            }
            left++;
        }
        for(int i=0;i<arr.length;i++){
            for(int j=0;j<arr.length;j++){
                if(arr[i][j]<10){
                    String s = "0"+Integer.toString(arr[i][j]);
                    if(j==(arr.length-1)){
                        System.out.print(s);
                    }else{
                        System.out.print(s+"-");
                    }
                }else{
                    if(j==(n-1)){
                        System.out.print(arr[i][j]);
                    }else{
                        System.out.print(arr[i][j]+"-");
                    }
                }
                if(j==n-1){
                    System.out.println();
                }
            }
        }
    }
}