java冒泡排序和选择排序详解

import java.util.Arrays;

public class BubbleSort {

     public static void main(String[] args) {

         // TODO Auto-generated method stub

         int arr[]= { 3 , 9 ,- 1 , 10 ,- 2 };

         //第i+1趟排序，将最大的数排在最后

         int temp= 0 ; //临时变量

         for ( int i= 0 ;i<arr.length- 1 ;i++) { //定义第几轮排序

          for ( int j= 0 ;j<arr.length- 1 -i;j++) {

              if (arr[j+ 1 ]<arr[j]) {

               temp=arr[j];

              arr[j]=arr[j+ 1 ];

              arr[j+ 1 ]=temp;

              }

              }

         System.out.println( "输出第" +(i+ 1 )+ "趟排序的结果" );

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

         }

         }

     }

import java.util.Arrays;

public class QuickSort {

     public static void main(String[] args) {

        //int []arr={ 8,3,2,1,7,4,6,5};

        int [] arr={ 101 , 34 , 109 , 1 };

        quicksort(arr);

     }

     public static void quicksort( int []arr){

         for ( int j= 0 ;j<arr.length- 1 ;j++) {

             int minindex=j; //假定当前下标为最小值下标

             int minnumber=arr[j]; //假定当前元素为最小值

             for ( int i = 1 +j; i < arr.length; i++) {

                 if (arr[i] < minnumber) { //若假定最小值并不是最小的

                     minnumber = arr[i]; //重置minnumber

                     minindex = i; //重置minindex

                 }

             }

             //将最小值交换

             arr[minindex] = arr[j];

             arr[j] = minnumber;

             System.out.println( "第" +(j+ 1 )+ "轮" );

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

         }

     }

}