diff --git a/step6.c b/step6.c
new file mode 100644
index 0000000..ec428f1
--- /dev/null
+++ b/step6.c
@@ -0,0 +1,141 @@
+#include <stdio.h>
+#include <string.h>
+
+typedef struct {
+    char id[20];
+    char clas[20];
+    char name[20];
+    double score1;
+    double score2;
+    double score3;
+    double score;
+} Student;
+
+void inputStudentInfo(Student *student) {
+    scanf("%s %s %s", student->id, student->clas, student->name);
+    scanf("%lf %lf %lf", &student->score1, &student->score2, &student->score3);
+    student->score = student->score1 + student->score2 + student->score3;
+}
+
+void displayStudentInfo(Student student, int isFirstInClass) {
+    if (isFirstInClass) {
+        printf("%s %s %s %.1lf %.1lf %.1lf",
+               student.clas, student.id, student.name,
+               student.score1, student.score2, student.score3);
+    } else {
+        printf("   %s %s %.1lf %.1lf %.1lf",
+               student.id, student.name,
+               student.score1, student.score2, student.score3);
+    }
+}
+
+int findStudentById(Student *students, int studentCount, char *id) {
+    for (int i = 0; i < studentCount; i++) {
+        if (strcmp(students[i].id, id) == 0) {
+            return i;
+        }
+    }
+    return -1;
+}
+
+void modifyStudentInfo(Student *students, int studentCount, char *id) {
+    int index = findStudentById(students, studentCount, id);
+    if (index != -1) {
+        printf("Please enter the modified information:\n");
+        inputStudentInfo(&students[index]);
+    } else {
+        printf("The relevant student was not found, and modification is not possible\n");
+    }
+
+}
+
+void bubbleSortByClassAndScore(Student *students, int studentCount) {
+    // 冒泡排序，先按班级从小到大，再按总成绩从大到小
+    for (int i = 0; i < studentCount - 1; i++) {
+        for (int j = 0; j < studentCount - i - 1; j++) {
+            if (strcmp(students[j].clas, students[j + 1].clas) > 0 ||
+                (strcmp(students[j].clas, students[j + 1].clas) == 0 && students[j].score < students[j + 1].score)) {
+                // 交换两个学生的信息
+                Student temp = students[j];
+                students[j] = students[j + 1];
+                students[j + 1] = temp;
+            }
+        }
+    }
+}
+
+int main() {
+    Student students[100];
+    int studentCount = 3;
+
+    // 初始化三个学生信息
+    strcpy(students[0].id, "10001");
+    strcpy(students[0].clas, "11");
+    strcpy(students[0].name, "Zhang");
+    students[0].score1 = 99.5;
+    students[0].score2 = 88.5;
+    students[0].score3 = 89.5;
+    students[0].score = students[0].score1 + students[0].score2 + students[0].score3;
+
+    strcpy(students[1].id, "10002");
+    strcpy(students[1].clas, "12");
+    strcpy(students[1].name, "Yang");
+    students[1].score1 = 77.9;
+    students[1].score2 = 56.5;
+    students[1].score3 = 87.5;
+    students[1].score = students[1].score1 + students[1].score2 + students[1].score3;
+
+    strcpy(students[2].id, "10003");
+    strcpy(students[2].clas, "11");
+    strcpy(students[2].name, "Liang");
+    students[2].score1 = 92.5;
+    students[2].score2 = 99.0;
+    students[2].score3 = 60.5;
+    students[2].score = students[2].score1 + students[2].score2 + students[2].score3;
+
+    bubbleSortByClassAndScore(students, studentCount);
+
+    // 输出所有学生信息
+    int isFirstInClass = 1;
+    for (int i = 0; i < studentCount; i++) {
+        if (i > 0 && strcmp(students[i].clas, students[i - 1].clas) == 0) {
+            isFirstInClass = 0;
+        } else {
+            isFirstInClass = 1;
+        }
+        displayStudentInfo(students[i], isFirstInClass);
+        printf("\n");
+    }
+
+    // 修改学生信息
+    char id[20];
+    printf("Please enter the student ID to be modified:");
+    scanf("%s", id);
+    modifyStudentInfo(students, studentCount, id);
+
+    // 再次排序并输出所有学生信息
+    bubbleSortByClassAndScore(students, studentCount);
+    int d=findStudentById(students, studentCount, id);
+    isFirstInClass = 1;
+    for (int i = 0; i < studentCount; i++) {
+        if (i > 0 && strcmp(students[i].clas, students[i - 1].clas) == 0) {
+            isFirstInClass = 0;
+        } else {
+            isFirstInClass = 1;
+        }
+        if (i == d) {
+         
+            displayStudentInfo(students[i], isFirstInClass);
+            printf("  modified\n");
+        }
+        else
+        {
+            displayStudentInfo(students[i], isFirstInClass);
+            printf("\n");
+
+        }
+    }
+
+    return 0;
+}
+