diff --git a/README.md b/README.md
index a91a3da..6d619bc 100644
--- a/README.md
+++ b/README.md
@@ -227,7 +227,26 @@ void AverSumofEveryCourse(STU stu[],int n,int m)
 ```
 voidSortbyScore(STU stu[],int n,int m,int(*compare)(float a,float b))
 {
-
+	int  i, j, k, t;
+	for (i=0; i<n-1; i++)
+	{
+		k = i;
+		for (j=i+1; j<n; j++)
+		{
+		if ((*compare)(stu[j].sum, stu[k].sum)) k = j;
+		}
+		if (k != i)
+		{		   
+		   for (t=0; t<m; t++)        //交换m门课程的成绩
+                    {
+                      SwapFloat(&stu[k].score[t], &stu[i].score[t]);
+                    }
+SwapFloat(&stu[k].sum, &stu[i].sum);    //交换总分 
+SwapFloat(&stu[k].aver, &stu[i].aver);  //交换平均分
+SwapLong(&stu[k].num, &stu[i].num);     //交换学号 
+SwapChar(stu[k].name, stu[i].name);     //交换姓名
+		}
+	}
 }
 ```
 
@@ -280,17 +299,18 @@ void SwapChar(char x[],chary[])
 }
 ```
 
-//函数功能：按选择法将数组 sum 的元素从低到高排序
+//函数功能：按选择法将数组 num 的元素从低到高排序
 ```
 void AsSortbyNum(STU stu[],int n,int m)
 {
-	int  i, j, k, t;
+     	int  i, j, k, t;
 	for (i=0; i<n-1; i++)
 	{
+			int  i, j, k, t;
 		k = i;
 		for (j=i+1; j<n; j++)
 		{
-		if ((*compare)(stu[j].sum, stu[k].sum)) k = j;
+		if (stu[j].num < stu[k].num) k = j;
 		}
 		if (k != i)
 		{