diff --git a/step7.c b/step7.c
new file mode 100644
index 0000000..d0c99d4
--- /dev/null
+++ b/step7.c
@@ -0,0 +1,122 @@
+#include <stdio.h>
+#include <string.h>
+
+#define MAX_STUDENTS 100
+
+typedef struct {
+    int id;
+    int class;
+    char name[20];
+    float scores[3];
+    float total;
+} Student;
+
+Student students[MAX_STUDENTS];
+int studentCount = 0;
+
+// 函数声明
+void inputAndSortStudents();
+int compareStudents(const void *a, const void *b);
+void queryStudents();
+void printStudents(Student *student);
+
+int main() {
+    inputAndSortStudents();
+    queryStudents();
+    return 0;
+}
+
+void addStudent(int id, int class, char *name, float score1, float score2, float score3) {
+    if (studentCount < MAX_STUDENTS) {
+        students[studentCount].id = id;
+        students[studentCount].class = class;
+        strcpy(students[studentCount].name, name);
+        students[studentCount].scores[0] = score1;
+        students[studentCount].scores[1] = score2;
+        students[studentCount].scores[2] = score3;
+        students[studentCount].total = score1 + score2 + score3;
+        studentCount++;
+    }
+}
+void inputAndSortStudents() {
+    // 这里应该有一个循环来输入学生信息
+    
+    addStudent(10001, 11, "Zhang", 99.5, 88.5, 89.5);
+    addStudent(10002, 12, "Yang", 77.9, 56.5, 87.5);
+    addStudent(10003, 11, "Liang", 92.5, 99.0, 60.5);
+    addStudent(10004, 11,"Cai", 89.6, 56.9, 90.5);
+    addStudent(10005, 14, "Fu", 55.6, 67.9, 98.9);
+    addStudent(10006, 12, "Mao", 22.1, 45.9, 99.2);
+    addStudent(10007, 13, "Zhan", 35.6, 67.9, 88.0);
+    
+    // 排序学生信息
+    qsort(students, studentCount, sizeof(Student), compareStudents);
+}
+
+int compareStudents(const void *a, const void *b) {
+    Student *studentA = (Student *)a;
+    Student *studentB = (Student *)b;
+    if (studentA->class != studentB->class) {
+        return studentA->class - studentB->class;
+    }
+    return (studentB->total - studentA->total); // 降序排列
+}
+
+void queryStudents() {
+    int queryType;
+    float minScore;
+    char namePattern[20];
+    int classStart, classEnd, idStart, idEnd;
+
+    printf("Enter query type (1: class range, 2: student ID range, 3: name pattern, 4: total score): ");
+    scanf("%d", &queryType);
+
+    switch (queryType) {
+        case 1:
+            printf("Enter class range (e.g., 11-13): ");
+            scanf("%d-%d", &classStart, &classEnd);
+            int i;
+            for (i = 0; i < studentCount; i++) {
+                if (students[i].class >= classStart && students[i].class <= classEnd) {
+                    printStudents(&students[i]);
+                }
+            }
+            break;
+        case 2:
+            printf("Enter student ID range (e.g., 10001-10004): ");
+            scanf("%d-%d", &idStart, &idEnd);
+            for (i = 0; i < studentCount; i++) {
+                if (students[i].id >= idStart && students[i].id <= idEnd) {
+                    printStudents(&students[i]);
+                }
+            }
+            break;
+        case 3:
+            printf("Enter name pattern (e.g., Zh*): ");
+            scanf("%s", namePattern);
+            for (i = 0; i < studentCount; i++) {
+                if (strstr(students[i].name, namePattern) != NULL) {
+                    printStudents(&students[i]);
+                }
+            }
+            break;
+        case 4:
+            printf("Enter minimum total score: ");
+            scanf("%f", &minScore);
+            for (i = 0; i < studentCount; i++) {
+                if (students[i].total >= minScore) {
+                    printStudents(&students[i]);
+                }
+            }
+            break;
+        default:
+            printf("Invalid query type.\n");
+            break;
+    }
+}
+
+void printStudents(Student *student) {
+    printf("%d %d %s %.1f %.1f %.1f\n", student->id, student->class, student->name,
+           student->scores[0], student->scores[1], student->scores[2]);
+}
+