1.冒泡排序

package com.cts.elt.sort;

import java.util.Arrays;

public class MaopaoSort {

    public int[] arr;


    public  void sort(){

        int in;
        int out;

        for (out =arr.length-1;out>1;out--){

            for (in=0;in<out;in++){

                if (arr[in]>arr[in+1]){

                    swap(in,in+1);

                }
            }

        }


    }

    public  void swap(int a,int b){

        int t =arr[a];
        arr[a]=arr[b];
        arr[b]=t;

    }

    public static void main(String [] args){

        MaopaoSort maopaoSort =new MaopaoSort();

        maopaoSort.arr =new int[]{1,8,4,7,2};

        maopaoSort.sort();

        System.out.println(Arrays.toString(maopaoSort.arr));
    }
}