数组排序的实现：自然升序排序，自然降序排序，数组倒置，随机排序

1.数组自然升序排序

int[] a={3,2,5,4,1};
Arrays.sort(a);
for(int arr:a) {
    System.out.print(arr + " ");
}

结果：1 2 3 4 5

2.自然降序排序

int[] a={3,2,5,4,1};
Arrays.sort(a);
for(int i=a.length-1;i>=0;i--) {
    System.out.print(a[i] + " ");
}

结果：5 4 3 2 1

3.数组倒置

public void testReverseSelf() throws Exception {
    System.out.println("use ReverseSelf");

    String[] strings = { "ramer", "jelly", "bean", "cake" };
    System.out.println("\t" + Arrays.toString(strings));
    for (int start = 0, end = strings.length - 1; start < end; start++, end--) {
        String temp = strings[end];
        strings[end] = strings[start];
        strings[start] = temp;
    }
    System.out.println("\t" + Arrays.toString(strings));
}

结果：
use ReverseSelf
[ramer, jelly, bean, cake]
[cake, bean, jelly, ramer]

4.随机排序

import java.lang.Math;

import java.util.Scanner;

class AarrayReverse

{

 public static void main(String args[])

 {

  int a[]=new int[20];

  for(int i=0;i<=15;i++)

  {

   Scanner sca=new Scanner(System.in);

   System.out.println("请输数组元素a["+"]");

   a[i]=sca.nextInt();

  }

  for(int i=0;i<=100;i++)

  {

   int middle=(int)(a.length/2*Math.random());

   int radius=(int)(middle*Math.random());

   int t;

   t=a[middle-radius+1];

   a[middle-radius+1]=a[middle+radius+3];

   a[middle+radius+3]=t;

  }

  for(int i=0;i
  System.out.print(a[i]+" ");

  System.out.println();

 }

}

[1]https://blog.youkuaiyun.com/u013337889/article/details/51243404
[2]http://www.111cn.net/jsp/Java/40825.htm