diff --git a/b8.c b/b8.c
new file mode 100644
index 0000000..e3b081a
--- /dev/null
+++ b/b8.c
@@ -0,0 +1,147 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+struct Student {
+    char *id;
+    char *clas;
+    char *name;
+    double score1;
+    double score2;
+    double score3;
+    double score;
+};
+
+void input(struct Student students[], int *count);
+void delete_student(struct Student students[], int *count);
+void select_student(struct Student students[], int count);
+void order_student(struct Student students[], int count);
+void output_student(struct Student students[], int count);
+void free_students(struct Student students[], int count);
+
+int main() {
+    struct Student students[100];  
+    int count = 0; 
+    int option;
+    do {
+        printf("1. input\n2. delete\n3. select\n4. order\n5. output\n6. quit\nplease input your option: ");
+        scanf("%d", &option);
+        switch (option) {
+            case 1:
+                input(students, &count);
+                break;
+            case 2:
+                delete_student(students, &count);
+                break;
+            case 3:
+                select_student(students, count);
+                break;
+            case 4:
+                order_student(students, count);
+                break;
+            case 5:
+                output_student(students, count);
+                break;
+            case 6:
+                printf("Exiting the program...\n");
+                break;
+            default:
+                printf("Invalid option, please try again.\n");
+        }
+    } while (option != 6);
+
+    free_students(students, count);
+
+    return 0;
+}
+
+void input(struct Student students[], int *count) {
+    char continue_input[5];
+    do {
+        if (*count >= 100) {
+            printf("Maximum number of students reached.\n");
+            break;
+        }
+
+        students[*count].id = (char *)malloc(sizeof(char) * 10);
+        students[*count].clas = (char *)malloc(sizeof(char) * 20);
+        students[*count].name = (char *)malloc(sizeof(char) * 20);
+        if (students[*count].id == NULL || students[*count].clas == NULL || students[*count].name == NULL) {
+            printf("Memory allocation failed.\n");
+            exit(1);
+        }
+
+        printf("Enter ID, Class, Name, Score1, Score2, Score3: ");
+        scanf("%s %s %s %lf %lf %lf", students[*count].id, students[*count].clas, students[*count].name,
+              &students[*count].score1, &students[*count].score2, &students[*count].score3);
+        students[*count].score = (students[*count].score1 + students[*count].score2 + students[*count].score3) / 3;
+
+        (*count)++;
+        printf("Continue input? (yes/no): ");
+        scanf("%s", continue_input);
+    } while (strcmp(continue_input, "yes") == 0);
+}
+
+void delete_student(struct Student students[], int *count) {
+    char id[10];
+    printf("Enter the ID of the student to delete: ");
+    scanf("%s", id);
+
+    for (int i = 0; i < *count; i++) {
+        if (strcmp(students[i].id, id) == 0) {
+            free(students[i].id);
+            free(students[i].clas);
+            free(students[i].name);
+
+            for (int j = i; j < *count - 1; j++) {
+                students[j] = students[j + 1];
+            }
+            (*count)--;
+            printf("Student with ID %s deleted successfully.\n", id);
+            return;
+        }
+    }
+    printf("Student with ID %s not found.\n", id);
+}
+
+void select_student(struct Student students[], int count) {
+    char id[10];
+    printf("Enter the ID of the student to select: ");
+    scanf("%s", id);
+
+    for (int i = 0; i < count; i++) {
+        if (strcmp(students[i].id, id) == 0) {
+            printf("ID: %s, Class: %s, Name: %s, Score1: %.2f, Score2: %.2f, Score3: %.2f, Average Score: %.2f\n",
+                   students[i].id, students[i].clas, students[i].name, students[i].score1, students[i].score2, students[i].score3, students[i].score);
+            return;
+        }
+    }
+    printf("Student with ID %s not found.\n", id);
+}
+
+void order_student(struct Student students[], int count) {
+    for (int i = 0; i < count - 1; i++) {
+        for (int j = 0; j < count - i - 1; j++) {
+            if (students[j].score < students[j + 1].score) {
+                struct Student temp = students[j];
+                students[j] = students[j + 1];
+                students[j + 1] = temp;
+            }
+        }
+    }
+    printf("Students ordered by average score.\n");
+}
+
+void output_student(struct Student students[], int count) {
+    for (int i = 0; i < count; i++) {
+        printf("ID: %s, Class: %s, Name: %s, Score1: %.2f, Score2: %.2f, Score3: %.2f, Average Score: %.2f\n",
+               students[i].id, students[i].clas, students[i].name, students[i].score1, students[i].score2, students[i].score3, students[i].score);
+    }
+}
+void free_students(struct Student students[], int count) {
+    for (int i = 0; i < count; i++) {
+        free(students[i].id);
+        free(students[i].clas);
+        free(students[i].name);
+    }
+}
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