diff --git a/c10代码.md b/c10代码.md
new file mode 100644
index 0000000..a1ff69f
--- /dev/null
+++ b/c10代码.md
@@ -0,0 +1,14 @@
+// 10函数功能：按选择法将数组num的元素值按从低到高排序 
+void AsSortbyNum(STU stu[], int n, int m)
+{
+    int  i, j, k, t;
+    for (i=0; i<n-1; i++)
+    {
+        K=i;
+        for(j=i+1;j<10;j++)
+        {
+            if((*compare)(stu[k]num.stu[j].num)) k=j;}
+        if(k!=i)
+        {t=stu[i].num;stu[i].num=stu[k].num;stu[k].num=t;}
+    }
+}
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diff --git a/c11代码.md b/c11代码.md
new file mode 100644
index 0000000..0a02e28
--- /dev/null
+++ b/c11代码.md
@@ -0,0 +1,24 @@
+// 11函数功能：交换法实现字符串按字典顺序排序 
+void AsSortbyNum(STU stu[], int n, int m)
+{
+    int  i, j, k, t;
+    for (i=0; i<n-1; i++)
+    {
+        k = i;
+        for (j=i+1; j<n; j++)
+        {
+            if (stu[j].num < stu[k].num)    k = j;
+        }
+        if (k != i)
+        {
+            for (t=0; t<m; t++)          
+              {
+                   SwapFloat(&stu[k].score[t], &stu[i].score[t]);
+            }
+SwapFloat(&stu[k].sum, &stu[i].sum);  
+SwapFloat(&stu[k].aver, &stu[i].aver);   
+SwapLong(&stu[k].num, &stu[i].num);     
+SwapChar(stu[k].name, stu[i].name);  
+        }
+    }
+}
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diff --git a/c12代码.md b/c12代码.md
new file mode 100644
index 0000000..c4c7572
--- /dev/null
+++ b/c12代码.md
@@ -0,0 +1,22 @@
+// 12函数功能：按学号查找学生成绩并显示查找结果 
+void SearchbyNum(STU stu[], int n, int m)
+{
+    long number;
+    int   i, j;
+    printf("Input the number you want to search:");
+    scanf("%ld", &number);
+    for(i=0;i<n;i++)
+    {
+    if (stu[i].num==number)
+        {
+            printf("%ld\t%s\t", stu[i].num, stu[i].name);
+            for (j=0; j<m; j++)
+            {
+                printf("%.0f\t", stu[i].score[j]);
+            }
+            printf("%.0f\t%.0f\n", stu[i].sum, stu[i].aver);
+            return;
+        }
+    printf("\nNot found!\n");
+}
+}
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diff --git a/c9代码.md b/c9代码.md
new file mode 100644
index 0000000..555dbe8
--- /dev/null
+++ b/c9代码.md
@@ -0,0 +1,8 @@
+// 9交换两个字符串 
+void  SwapChar(char x[], char y[])
+{
+char temp[MAX_LEN];
+strcpy(temp, x);
+strcpy(x, y);
+strcpy(y, temp);
+}
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