diff --git a/b7.c b/b7.c
new file mode 100644
index 0000000..f0f5402
--- /dev/null
+++ b/b7.c
@@ -0,0 +1,125 @@
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+
+#define MAX_STUDENTS 100
+
+typedef struct Student {
+    int id;
+    int class_num;
+    char name[20];
+    double score1;
+    double score2;
+    double score3;
+    double total_score;
+} Student;
+
+void calculateTotalScore(Student *students, int num) {
+	int i;
+    for (i = 0; i < num; i++) {
+        students[i].total_score = students[i].score1 + students[i].score2 + students[i].score3;
+    }
+}
+void swap(Student *a, Student *b) {
+    Student temp = *a;
+    *a = *b;
+    *b = temp;
+}
+
+void sortStudents(Student *students, int num) {
+	int i,j;
+    for ( i = 0; i < num - 1; i++) {
+        for ( j = 0; j < num - i - 1; j++) {
+            if (students[j].class_num > students[j + 1].class_num) {
+                swap(&students[j], &students[j + 1]);
+            } else if (students[j].class_num == students[j + 1].class_num &&
+                       students[j].total_score < students[j + 1].total_score) {
+                swap(&students[j], &students[j + 1]);
+            }
+        }
+    }
+}
+
+void searchStudents(Student *students, int num, char *query_type, char *query_content, Student *result, int *result_num) {
+    *result_num = 0;
+    int i;
+    if (query_type[0] == '1') {  
+        int start_class, end_class;
+        sscanf(query_content, "%d-%d", &start_class, &end_class);
+        for (i = 0; i < num; i++) {
+            if (students[i].class_num >= start_class && students[i].class_num <= end_class) {
+                result[*result_num] = students[i];
+                (*result_num)++;
+            }
+        }
+    } else if (query_type[0] == '2') { 
+        int start_id, end_id;
+        sscanf(query_content, "%d-%d", &start_id, &end_id);
+        for ( i = 0; i < num; i++) {
+            if (students[i].id >= start_id && students[i].id <= end_id) {
+                result[*result_num] = students[i];
+                (*result_num)++;
+            }
+        }
+    } else if (query_type[0] == '3') {
+        char prefix[20];
+        strcpy(prefix, query_content);
+        for (i = 0; i < num; i++) {
+            if (strncmp(students[i].name, prefix, strlen(prefix)) == 0) {
+                result[*result_num] = students[i];
+                (*result_num)++;
+            }
+        }
+    } else if (query_type[0] == '4') {
+        double min_score;
+        sscanf(query_content, "%lf", &min_score);
+        for ( i = 0; i < num; i++) {
+            if (students[i].total_score >= min_score) {
+                result[*result_num] = students[i];
+                (*result_num)++;
+            }
+        }
+    } else if (query_type[0] == '5') {
+        int class_num;
+        int start_id, end_id;
+        sscanf(query_content, "%d.%d-%d", &class_num, &start_id, &end_id);
+        for ( i = 0; i < num; i++) {
+            if (students[i].class_num == class_num && students[i].id >= start_id && students[i].id <= end_id) {
+                result[*result_num] = students[i];
+                (*result_num)++;
+            }
+        }
+    }
+}
+
+int main() {
+    Student students[MAX_STUDENTS] = {
+        {10001, 11, "Zhang", 99.5, 88.5, 89.5, 0},
+        {10002, 12, "Yang", 77.9, 56.5, 87.5, 0},
+        {10003, 11, "Liang", 92.5, 99.0, 60.5, 0},
+        {10004, 11, "Cai", 89.6, 56.9, 90.5, 0},
+        {10005, 14, "Fu", 55.6, 67.9, 98.9, 0},
+        {10006, 12, "Mao", 22.1, 45.9, 99.2, 0},
+        {10007, 13, "Zhan", 35.6, 67.9, 88.0, 0}
+    };
+    int num_students = 7,i;
+
+    calculateTotalScore(students, num_students);
+
+    char query_type[10];
+    char query_content[50];
+    
+    scanf("%s %s", query_type, query_content);
+
+    Student result[MAX_STUDENTS];
+    int result_num;
+    searchStudents(students, num_students, query_type, query_content, result, &result_num);
+    sortStudents(result, result_num);
+
+    for (i = 0; i < result_num; i++) {
+        printf("%d %d %s %.1lf %.1lf %.1lf\n", result[i].id, result[i].class_num, result[i].name,
+               result[i].score1, result[i].score2, result[i].score3);
+    }
+
+    return 0;
+}