diff --git a/4.c b/4.c
new file mode 100644
index 0000000..2dca1e9
--- /dev/null
+++ b/4.c
@@ -0,0 +1,65 @@
+#include <stdio.h>
+
+// 学生信息的结构体
+struct Student {
+    int id;
+    int class;
+    float score1;
+    float score2;
+    float score3;
+};
+
+// 插入新学生并保持数组有序的函数
+void insertStudent(struct Student students[], int* numStudents, struct Student newStudent) {
+    int i, j;
+
+    // 检查学号是否已存在
+    for (i = 0; i < *numStudents; i++) {
+        if (students[i].id == newStudent.id) {
+            printf("已存在学号的信息。\n");
+            return;
+        }
+    }
+
+    // 插入新学生信息并保持数组有序
+    students[*numStudents] = newStudent;
+    (*numStudents)++;
+    for (i = 0; i < *numStudents - 1; i++) {
+        for (j = 0; j < *numStudents - i - 1; j++) {
+            if (students[j].class > students[j + 1].class ||
+                (students[j].class == students[j + 1].class && students[j].score1 < students[j + 1].score1)) {
+                struct Student temp = students[j];
+                students[j] = students[j + 1];
+                students[j + 1] = temp;
+            }
+        }
+    }
+
+    // 输出所有学生信息，包括插入标志
+    for (i = 0; i < *numStudents; i++) {
+        printf("%d %d %.1f %.1f %.1f", students[i].id, students[i].class, students[i].score1, students[i].score2, students[i].score3);
+        if (i == *numStudents - 2) {
+            printf(" inserted");
+        }
+        printf("\n");
+    }
+}
+
+int main() {
+    // 已有的三个学生信息
+    struct Student students[3] = {
+        {10001, 11, 99.5, 88.5, 89.5},
+        {10002, 12, 77.9, 56.5, 87.5},
+        {10003, 11, 92.5, 99.0, 60.5}
+    };
+    int numStudents = 3;
+
+    // 输入新学生信息
+    struct Student newStudent;
+    scanf("%d %d %f %f %f", &newStudent.id, &newStudent.class, &newStudent.score1, &newStudent.score2, &newStudent.score3);
+
+    // 插入新学生信息并输出
+    insertStudent(students, &numStudents, newStudent);
+
+    return 0;
+}
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