SELECTION SORT：选择排序算法，每次从未完成排序的部分选出最小的插入未完成排序元素的最前面
代码实现比较好写：
import java.util.*;
public class SelectSort
{ public static void main(String[] args) { System.out.println("Hello World!");int [] a = {3,44,38,5,47,15,36,26,27,2,46,4,19,50,48};
selectionSort(a);
}public static void selectionSort(int [] a)
{ int length = a.length;//int min = -1;
int minPos = -1;//记录当前最小的值在数组中的位置
for(int i = 0; i < length-1; i++)//需要从左开始循环length-1次
{ minPos = i;//循环前，将最前面没有排序的值作为最小值记录下来其位置 for( int j = i + 1; j < length; j++) { if(a[minPos] > a[j])//从左到右开始比较还未完成排序的数字，保存最小数字的位置 { minPos = j; } } System.out.print(a[i]+":"+a[minPos]); int tem = a[i];//交换最小数字和刚开始排序开始的位置a[i] = a[minPos];
a[minPos] = tem; System.out.println(Arrays.toString(a)); } } }运行结果：
E:\java\java_test\sortprogram>java SelectSort
Hello World! 3:2[2, 44, 38, 5, 47, 15, 36, 26, 27, 3, 46, 4, 19, 50, 48] 44:3[2, 3, 38, 5, 47, 15, 36, 26, 27, 44, 46, 4, 19, 50, 48] 38:4[2, 3, 4, 5, 47, 15, 36, 26, 27, 44, 46, 38, 19, 50, 48] 5:5[2, 3, 4, 5, 47, 15, 36, 26, 27, 44, 46, 38, 19, 50, 48] 47:15[2, 3, 4, 5, 15, 47, 36, 26, 27, 44, 46, 38, 19, 50, 48] 47:19[2, 3, 4, 5, 15, 19, 36, 26, 27, 44, 46, 38, 47, 50, 48] 36:26[2, 3, 4, 5, 15, 19, 26, 36, 27, 44, 46, 38, 47, 50, 48] 36:27[2, 3, 4, 5, 15, 19, 26, 27, 36, 44, 46, 38, 47, 50, 48] 36:36[2, 3, 4, 5, 15, 19, 26, 27, 36, 44, 46, 38, 47, 50, 48] 44:38[2, 3, 4, 5, 15, 19, 26, 27, 36, 38, 46, 44, 47, 50, 48] 46:44[2, 3, 4, 5, 15, 19, 26, 27, 36, 38, 44, 46, 47, 50, 48] 46:46[2, 3, 4, 5, 15, 19, 26, 27, 36, 38, 44, 46, 47, 50, 48] 47:47[2, 3, 4, 5, 15, 19, 26, 27, 36, 38, 44, 46, 47, 50, 48] 50:48[2, 3, 4, 5, 15, 19, 26, 27, 36, 38, 44, 46, 47, 48, 50]E:\java\java_test\sortprogram>
INSERECTION SORT:插入排序-----代码加了注释，感觉很详细了。
import java.util.*;
public class InsertSort
{ public static void main(String[] args) { System.out.println("Hello World!"); int [] a = {3,44,38,5,47,15,36,26,27,2,46,4,19,50,48}; insertionSort(a); }public static void insertionSort(int a[])
{ int length = a.length;for(int i = 1; i < length; i++)//从第二个元素开始，第一元素默认以排好
{ int insert = a[i];//准备要插入的元素，把要插入元素的位置空出来，为了能移动元素 for(int j = i-1; j >= 0; j--)//从要插入元素位置往前查，以便确认插入元素要插入的位置 { if(a[j] > insert)//如果当前元素大于要准备插入的元素，则将该元素往后移动一位 { int tem = a[j]; a[j] = a[j + 1]; a[j+1] = tem; } else//如果当前元素小要准备插入的元素，则将要准备插入的元素插入该元素的后面，同时退出这次循环，开始排下一个元素 { int tem1 = a[j+1]; a[j+1] = insert; break; } }System.out.println(Arrays.toString(a));
} } }运行结果：
Hello World!
[3, 44, 38, 5, 47, 15, 36, 26, 27, 2, 46, 4, 19, 50, 48] [3, 38, 44, 5, 47, 15, 36, 26, 27, 2, 46, 4, 19, 50, 48] [3, 5, 38, 44, 47, 15, 36, 26, 27, 2, 46, 4, 19, 50, 48] [3, 5, 38, 44, 47, 15, 36, 26, 27, 2, 46, 4, 19, 50, 48] [3, 5, 15, 38, 44, 47, 36, 26, 27, 2, 46, 4, 19, 50, 48] [3, 5, 15, 36, 38, 44, 47, 26, 27, 2, 46, 4, 19, 50, 48] [3, 5, 15, 26, 36, 38, 44, 47, 27, 2, 46, 4, 19, 50, 48] [3, 5, 15, 26, 27, 36, 38, 44, 47, 2, 46, 4, 19, 50, 48] [2, 3, 5, 15, 26, 27, 36, 38, 44, 47, 46, 4, 19, 50, 48] [2, 3, 5, 15, 26, 27, 36, 38, 44, 46, 47, 4, 19, 50, 48] [2, 3, 4, 5, 15, 26, 27, 36, 38, 44, 46, 47, 19, 50, 48] [2, 3, 4, 5, 15, 19, 26, 27, 36, 38, 44, 46, 47, 50, 48] [2, 3, 4, 5, 15, 19, 26, 27, 36, 38, 44, 46, 47, 50, 48] [2, 3, 4, 5, 15, 19, 26, 27, 36, 38, 44, 46, 47, 48, 50]E:\java\java_test\sortprogram>