diff --git a/8.c b/8.c
new file mode 100644
index 0000000..7d60bc7
--- /dev/null
+++ b/8.c
@@ -0,0 +1,154 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+// 定义学生结构体
+struct Student {
+    char id[20];
+    char clas[20];
+    char name[20];
+    double score1;
+    double score2;
+    double score3;
+    double score;
+};
+
+// 全局学生数组
+struct Student* students[100];
+int studentCount = 0;
+
+// 菜单函数
+void printMenu() {
+    printf("1. Input\n");
+    printf("2. Delete\n");
+    printf("3. Select\n");
+    printf("4. Order\n");
+    printf("5. Output\n");
+    printf("6. Quit\n");
+    printf("Please input your option: ");
+}
+
+// 学生信息录入函数
+void inputStudent() {
+    if (studentCount < 100) {
+        struct Student* student = (struct Student*)malloc(sizeof(struct Student));
+        printf("Id: ");
+        scanf("%s", student->id);
+        printf("Class: ");
+        scanf("%s", student->clas);
+        printf("Name: ");
+        scanf("%s", student->name);
+        printf("Score1: ");
+        scanf("%lf", &student->score1);
+        printf("Score2: ");
+        scanf("%lf", &student->score2);
+        printf("Score3: ");
+        scanf("%lf", &student->score3);
+        student->score = student->score1 + student->score2 + student->score3;
+        students[studentCount++] = student;
+    }
+    else {
+        printf("Student database is full!\n");
+    }
+}
+
+// 学生信息删除函数
+void deleteStudent() {
+    char deleteId[20];
+    printf("Enter student ID or name to delete: ");
+    scanf("%s", deleteId);
+
+    int deleted = 0;
+    for (int i = 0; i < studentCount; i++) {
+        if (strcmp(students[i]->id, deleteId) == 0 || strcmp(students[i]->name, deleteId) == 0) {
+            free(students[i]);
+            for (int j = i; j < studentCount - 1; j++) {
+                students[j] = students[j + 1];
+            }
+            studentCount--;
+            deleted = 1;
+            i--;
+        }
+    }
+
+    if (deleted == 0) {
+        printf("Student not found.\n");
+    }
+}
+
+// 学生信息查询函数
+void selectStudent() {
+    char query[20];
+    printf("Enter student ID or class to select: ");
+    scanf("%s", query);
+
+    int found = 0;
+    for (int i = 0; i < studentCount; i++) {
+        if (strcmp(students[i]->id, query) == 0 || strcmp(students[i]->clas, query) == 0) {
+            printf("%s, %s, %s, %.1lf, %.1lf, %.1lf, %.1lf\n", students[i]->id, students[i]->clas, students[i]->name, students[i]->score1, students[i]->score2, students[i]->score3, students[i]->score);
+            found = 1;
+        }
+    }
+
+    if (found == 0) {
+        printf("There is no eligible student.\n");
+    }
+}
+
+// 学生信息排序函数
+void orderStudents() {
+    for (int i = 0; i < studentCount; i++) {
+        for (int j = i + 1; j < studentCount; j++) {
+            if (strcmp(students[i]->clas, students[j]->clas) > 0 || (strcmp(students[i]->clas, students[j]->clas) == 0 && students[i]->score < students[j]->score)) {
+                struct Student* temp = students[i];
+                students[i] = students[j];
+                students[j] = temp;
+            }
+        }
+    }
+}
+
+// 学生信息输出函数
+void outputStudents() {
+    for (int i = 0; i < studentCount; i++) {
+        printf("%s, %s, %s, %.1lf, %.1lf, %.1lf, %.1lf\n", students[i]->id, students[i]->clas, students[i]->name, students[i]->score1, students[i]->score2, students[i]->score3, students[i]->score);
+    }
+}
+
+int main() {
+    int option;
+    do {
+        printMenu();
+        scanf("%d", &option);
+        switch (option) {
+        case 1:
+            inputStudent();
+            break;
+        case 2:
+            deleteStudent();
+            break;
+        case 3:
+            selectStudent();
+            break;
+        case 4:
+            orderStudents();
+            outputStudents();
+            break;
+        case 5:
+            outputStudents();
+            break;
+        case 6:
+            // 退出程序
+            break;
+        default:
+            printf("Invalid option. Please try again.\n");
+        }
+    } while (option != 6);
+
+    // 释放内存
+    for (int i = 0; i < studentCount; i++) {
+        free(students[i]);
+    }
+
+    return 0;
+}