diff --git a/7th.c b/7th.c
new file mode 100644
index 0000000..b8c4ca7
--- /dev/null
+++ b/7th.c
@@ -0,0 +1,147 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#define MAX_STUDENTS 100
+typedef struct {
+    int id;
+    int class;
+    char name[20];
+    float scores[3];
+} Student;
+Student students[MAX_STUDENTS];
+int studentCount = 0;
+//已知数据 
+void readStudents() {
+    const int count = 7;
+    static const int ids[] = {10001, 10002, 10003, 10004, 10005, 10006, 10007};
+    static const int classes[] = {11, 12, 11, 11, 14, 12, 13};
+    static const char *names[] = {"Zhang", "Yang", "Liang", "Cai", "Fu", "Mao", "Zhan"};
+    static const float scores[][3] = {{99.5, 88.5, 89.5}, {77.9, 56.5, 87.5}, {92.5, 99.0, 60.5},
+                                      {89.6, 56.9, 90.5}, {55.6, 67.9, 98.9}, {22.1, 45.9, 99.2},
+                                      {35.6, 67.9, 88.0}};
+    int i,j; 
+    for (i = 0; i < count; ++i) {
+        students[i].id = ids[i];
+        students[i].class = classes[i];
+        strcpy(students[i].name, names[i]);
+        for (j = 0; j < 3; ++j) {
+            students[i].scores[j] = scores[i][j];
+        }
+    }
+    studentCount = count;
+}
+
+// 比较函数，用于qsort
+int compareStudents(const void *a, const void *b) {
+    Student *sa = (Student *)a;
+    Student *sb = (Student *)b;
+    if (sa->class != sb->class) {
+        return sa->class - sb->class;
+    } else {
+        float scoreA = sa->scores[0] + sa->scores[1] + sa->scores[2];
+        float scoreB = sb->scores[0] + sb->scores[1] + sb->scores[2];
+        return scoreB > scoreA ? 1 : -1;
+    }
+}
+// 对学生信息进行排序
+void sortStudents(Student *students, int n) {
+    qsort(students, n, sizeof(Student), compareStudents);
+}
+// 根据查询条件筛选学生信息
+void filterStudents(Student *students, int n, char *query, Student **result, int *resultCount) {
+    *resultCount = 0;
+    char type;
+    sscanf(query, "%c", &type);
+    switch (type) {
+        case '1': {
+            int startClass, endClass;
+            sscanf(query, "%*c %d-%d", &startClass, &endClass);
+            int l;
+			for (l = 0; l< n; ++l) {
+                if (students[l].class >= startClass && students[l].class <= endClass) {
+                    result[*resultCount] = &students[l];
+                    (*resultCount)++;
+                }
+            }
+            break;
+        }
+        case '2': {
+            int startId, endId;
+            sscanf(query, "%*c %d-%d", &startId, &endId);
+            int m;
+			for ( m = 0; m < n; ++m) {
+                if (students[m].id >= startId && students[m].id <= endId) {
+                    result[*resultCount] = &students[m];
+                    (*resultCount)++;
+                }
+            }
+            break;
+        }
+        case '3': {
+            char prefix[20];
+            sscanf(query, "%*c %s", prefix);
+            prefix[strcspn(prefix,"*")]=0;
+            int i1;
+            for (i1 = 0; i1 < n; ++i1) {
+                if (strncmp(students[i1].name, prefix, strlen(prefix)) == 0) {
+                    result[*resultCount] = &students[i1];
+                    (*resultCount)++;
+                }
+            }
+            break;
+        }
+        case '4': {
+            float minScore;
+            sscanf(query, "%*c %f", &minScore);
+            int i2;
+            for ( i2 = 0; i2 < n; ++i2) {
+                float totalScore = students[i2].scores[0] + students[i2].scores[1] + students[i2].scores[2];
+                if (totalScore >= minScore) {
+                    result[*resultCount] = &students[i2];
+                    (*resultCount)++;
+                }
+            }
+            break;
+        }
+        case '5': {
+            int class, startId, endId;
+            sscanf(query, "%*c %d.%d-%d", &class, &startId, &endId);
+            int i3;
+			for (i3 = 0; i3 < n; ++i3) {
+                if (students[i3].class == class && students[i3].id >= startId && students[i3].id <= endId) {
+                    result[*resultCount] = &students[i3];
+                    (*resultCount)++;
+                }
+            }
+            break;
+        }
+        default:
+            printf("Invalid query format.\n");
+            break;
+    }
+}
+
+// 输出学生信息
+void printStudents(Student *students[], int n) {
+	int i4;
+    for (i4 = 0; i4 < n; ++i4) {
+        printf("%d %d %s %.1f %.1f %.1f\n", students[i4]->id, students[i4]->class, students[i4]->name,
+               students[i4]->scores[0], students[i4]->scores[1], students[i4]->scores[2]);
+    }
+}
+int main() {
+    readStudents();
+    sortStudents(students, studentCount);
+
+    char query[100];
+    fgets(query, sizeof(query), stdin);
+    query[strcspn(query, "\n")] = 0; // 移除换行符
+
+    Student *results[MAX_STUDENTS];
+    int resultCount;
+    filterStudents(students, studentCount, query, results, &resultCount);
+
+    printStudents(results, resultCount);
+
+    return 0;
+}