diff --git a/Task7.c b/Task7.c
new file mode 100644
index 0000000..042e049
--- /dev/null
+++ b/Task7.c
@@ -0,0 +1,138 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+struct Student{
+		int stunumber;
+		int class;
+		char name[10];
+		float grade1;
+		float grade2;
+		float grade3;
+		float sum;
+		}students[7]={
+		{10001,11,"Zhang",99.5,88.5,89.5,99.5+88.5+89.5},
+		{10002,12,"Yang",77.9,56.5,87.5,77.9+56.5+87.5},				
+		{10003,11,"Liang",92.5,99.0,60.5,92.5+99.0+60.5},
+		{10004,11,"Cai",89.6,56.9,90.5,89.6+56.9+90.5},
+		{10005,14,"Fu",55.6,67.9,98.9,55.6+67.9+98.9},
+		{10006,12,"Mao",22.1,45.9,99.2,22.1+45.9+99.2},
+		{10007,13,"Zhan",35.6,67.9,88.0,35.6+67.9+88.60}};
+//一系列索引变量 
+int class_idx,min_idx,max_idx,i,n,j;
+float sum_idx;
+char name_idx[10];
+void selection_sort(struct Student arr[], int n) {
+    int i, j, min_idx;
+    //一一检索每个结构体中class的值 
+    for (i = 0; i < n-1; i++) {
+        // 找到最小值的位置 
+        min_idx = i;
+        for (j = i+1; j < n; j++)
+        {
+		
+		
+            if (arr[j].class < arr[min_idx].class)
+            {
+                min_idx = j;
+       		}
+       		else if(arr[j].class == arr[min_idx].class)
+       		{
+       			if(arr[j].sum > arr[min_idx].sum)
+       			{
+       				min_idx=j;
+				}
+			}
+		}
+        // 通过交换位置实现排序
+        struct Student temp = arr[min_idx];
+        arr[min_idx] = arr[i];
+        arr[i] = temp;
+    }
+}
+void print_student(struct Student *s) {
+    printf("%d %d %s %.1f %.1f %.1f \n", s->stunumber, s->class, s->name, s->grade1, s->grade2, s->grade3);
+}
+int main(){
+
+	
+	void selection_sort(struct Student arr[], int n);
+	void print_student(struct Student *s);
+	
+	selection_sort(students,7);
+	int Section_idx;
+	printf("请输入类别\n");
+	scanf("%d",&Section_idx);//输入类别 
+	switch(Section_idx)
+	{
+		case 1:goto section1;break;
+		case 2:goto section2;break;
+		case 3:goto section3;break;
+		case 4:goto section4;break;
+		case 5:goto section5;break;
+		default:printf("输入错误");
+	}
+	return 0;
+section1://查找指定班级范围内的学生 
+	printf("请输入您要查找的信息（格式：班级-班级）\n"); //班级-班级 
+	scanf("%d-%d",&min_idx,&max_idx);
+	for(i=0;i < 7;i++)
+	{
+		if(students[i].class>=min_idx&&students[i].class<=max_idx)
+		{
+			printf("%d %d %s %.1f %.1f %.1f \n", students[i].stunumber, students[i].class, students[i].name, students[i].grade1, students[i].grade2, students[i].grade3);
+		}
+	}
+	return 0;
+section2://查找指定学号范围的学生 
+	printf("请输入您要查找的信息（格式：学号-学号）\n"); //学号-学号 
+	scanf("%d-%d",&min_idx,&max_idx);
+	for(i=0;i < 7;i++)
+	{
+		if(students[i].stunumber >= min_idx&&students[i].stunumber <= max_idx)
+			printf("%d %d %s %.1f %.1f %.1f \n", students[i].stunumber, students[i].class, students[i].name, students[i].grade1, students[i].grade2, students[i].grade3);
+	}
+	
+	return 0;
+section3://查找指定名字开头字母的学生 
+	printf("请输入您要查找的信息（格式：开头字母+*）\n"); //字母* 
+	scanf("%s",name_idx);
+	for(i=0;i<7;i++)
+	{
+		n=strlen(name_idx)-1;
+		for(j=0;j<strlen(name_idx)-1;j++)
+		{
+			if(name_idx[j]==students[i].name[j])
+			{
+				n--;
+			}
+		}
+		if(n==0)
+		{
+			printf("%d %d %s %.1f %.1f %.1f \n", students[i].stunumber, students[i].class, students[i].name, students[i].grade1, students[i].grade2, students[i].grade3);
+		}
+	}
+	return 0;
+section4://查找大于指定总成绩的学生 
+	printf("请输入您要查找的信息（格式：总成绩（小数形式）\n"); //班级.学号-学号 
+	scanf("%f",&sum_idx);
+	for(i = 0;i < 7;i++)
+	{
+		if(students[i].sum>=sum_idx)
+		{
+			printf("%d %d %s %.1f %.1f %.1f \n", students[i].stunumber, students[i].class, students[i].name, students[i].grade1, students[i].grade2, students[i].grade3);
+		}
+	}
+	return 0;
+section5://查找指定班级下指定学号范围内的学生 
+	printf("请输入您要查找的信息（格式：班级+.+学号-学号）\n"); 
+	scanf("%d.%d-%d",&class_idx,&min_idx,&max_idx);
+	for(i = 0;i < 7;i++)
+	{
+		if(students[i].class==class_idx&&students[i].stunumber>=min_idx&&students[i].stunumber<=max_idx)
+		{
+			printf("%d %d %s %.1f %.1f %.1f \n", students[i].stunumber, students[i].class, students[i].name, students[i].grade1, students[i].grade2, students[i].grade3);
+		}
+	}
+	return 0;
+}