diff --git a/README.md b/README.md
index eab80b8..487d3b7 100644
--- a/README.md
+++ b/README.md
@@ -1 +1,104 @@
 # Student_registration_management_system
+//步骤3//
+#include <stdio.h>
+
+struct Student {
+    int id;
+    float mathGrade;
+    float physicsGrade;
+    float englishGrade;
+    float totalGrade;
+    float averageGrade;
+};
+
+void displayMenu() {
+    printf("                              1.Input\n");
+    printf("                              2.Output\n");
+    printf("                              3.Order\n");
+    printf("                              4.Quit\n");
+}
+
+void makeThingsOrdered() {
+    printf("You are trying to Make things ordered\n");
+}
+
+void quitProgram() {
+    printf("You are about to Quit\n");
+}
+
+void displayWrongInput() {
+    printf("Wrong input\n");
+}
+
+void inputStudentInfo(struct Student students[3]) {
+   
+
+    for (int i = 0; i < 3; ++i) {
+        printf("Student %d:\n", i + 1);
+
+        // Input student details
+        
+        scanf("%d", &students[i].id);
+
+        
+        scanf("%f", &students[i].mathGrade);
+
+       
+        scanf("%f", &students[i].physicsGrade);
+
+        
+        scanf("%f", &students[i].englishGrade);
+
+        // Calculate total and average grades
+        students[i].totalGrade = students[i].mathGrade + students[i].physicsGrade + students[i].englishGrade;
+        students[i].averageGrade = students[i].totalGrade / 3;
+    }
+}
+
+void displayStudentInfo(struct Student students[3]) {
+    // Sort students based on total grade
+    for (int i = 0; i < 2; ++i) {
+        for (int j = 0; j < 2 - i; ++j) {
+            if (students[j].totalGrade > students[j + 1].totalGrade) {
+                struct Student temp = students[j];
+                students[j] = students[j + 1];
+                students[j + 1] = temp;
+            }
+        }
+    }
+
+    // Display sorted student info
+    for (int i = 0; i < 3; ++i) {
+        printf("学号 %d,总成绩 %.1f,平均成绩 %.1f\n", students[i].id, students[i].totalGrade, students[i].averageGrade);
+    }
+}
+
+int main() {
+    char choice;
+    struct Student students[3];
+
+    do {
+        displayMenu();
+        printf("Enter your choice: ");
+        scanf(" %c", &choice);
+
+        switch (choice) {
+            case 'i':
+                inputStudentInfo(students);
+                break;
+            case 'o':
+                displayStudentInfo(students);
+                break;
+            case 'm':
+                makeThingsOrdered();
+                break;
+            case 'q':
+                quitProgram();
+                break;
+            default:
+                displayWrongInput();
+        }
+    } while (choice != '4');
+
+    return 0;
+}