diff --git a/xueji.c b/xueji.c
new file mode 100644
index 0000000..3b964aa
--- /dev/null
+++ b/xueji.c
@@ -0,0 +1,144 @@
+#define _CRT_SECURE_NO_WARNINGS
+#include <stdio.h>  
+#include <stdlib.h>  
+#include <string.h>  
+
+#define MAX_STUDENTS 100  
+
+typedef struct {
+    char id[10];
+    char class[10];
+    char name[20];
+    double score1;
+    double score2;
+    double score3;
+    double score;
+} Student;
+
+Student students[MAX_STUDENTS];
+int studentCount = 0;
+
+void inputStudent() {
+    while (1) {
+        Student newStudent;
+        char option[10];
+        printf("Id ");
+        scanf("%s", newStudent.id);
+        printf("class ");
+        scanf("%s", newStudent.class);
+        printf("name ");
+        scanf("%s", newStudent.name);
+        printf("score1 ");
+        scanf("%lf", &newStudent.score1);
+        printf("score2 ");
+        scanf("%lf", &newStudent.score2);
+        printf("score3 ");
+        scanf("%lf", &newStudent.score3);
+        newStudent.score = (newStudent.score1 + newStudent.score2 + newStudent.score3);
+
+        students[studentCount++] = newStudent;
+
+        printf("continue?\n");
+        scanf("%s", &option);
+        if (strcmp(option, "no") == 0) {
+            break;
+        }
+    }
+}
+
+void outputStudents() {
+    for (int i = 0; i < studentCount; i++) {
+        printf("%s, %s, %s, %.1f, %.1f, %.1f, %.1f\n",
+            students[i].id, students[i].class, students[i].name,
+            students[i].score1, students[i].score2, students[i].score3,
+            students[i].score);
+    }
+}
+
+void deleteStudent() {
+    while (studentCount > 1) {
+        char id[10];
+        scanf("%s", id);
+        char option[10];
+        for (int i = 0; i < studentCount; i++) {
+            if (strcmp(students[i].id, id) == 0 || strcmp(students[i].name, id) == 0) {
+                for (int j = i; j < studentCount - 1; j++) {
+                    students[j] = students[j + 1];
+                }
+                studentCount--;
+            }
+        }
+        outputStudents();
+        printf("continue?\n");
+        scanf("%s", &option);
+        if (strcmp(option, "no") == 0) {
+            break;
+        }
+    }
+}
+
+void selectStudent() {
+    while (1) {
+        char id[10];
+        scanf("%s", id);
+        int flag = 0;
+        char option[10];
+
+        for (int i = 0; i < studentCount; i++) {
+            if (strcmp(students[i].id, id) == 0 || strcmp(students[i].class, id) == 0) {
+                printf("%s, %s, %s, %.1f, %.1f, %.1f, %.1f\n",
+                    students[i].id, students[i].class, students[i].name,
+                    students[i].score1, students[i].score2, students[i].score3,
+                    students[i].score);
+                flag = 1;
+            }
+        }
+        if (flag == 0) {
+            printf("there is no eligible student\n");
+        }
+        printf("continue?\n");
+        scanf("%s", &option);
+        if (strcmp(option, "no") == 0) {
+            break;
+        }
+    }
+}
+
+int compare(const void* a, const void* b) {
+    Student* studentA = (Student*)a;
+    Student* studentB = (Student*)b;
+    if (strcmp(studentA->class, studentB->class) == 0) {
+        return (studentB->score - studentA->score > 0) ? 1 : -1;
+    }
+    return strcmp(studentA->class, studentB->class);
+}
+
+void orderStudents() {
+    qsort(students, studentCount, sizeof(Student), compare);
+    outputStudents();
+}
+
+int main() {
+    int option;
+    do {
+        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\n");
+        scanf("%d", &option);
+
+        switch (option) {
+        case 1: inputStudent(); break;
+        case 2: deleteStudent(); break;
+        case 3: selectStudent();  break;
+        case 4: orderStudents();  break;
+        case 5: outputStudents();  break;
+        case 6: break;
+        }
+    } while (option != 6);
+
+    return 0;
+}
\ No newline at end of file