Update README.md

README.md

@@ -1,2 +1,183 @@
 # GradeBookPlus
+#include <iostream>
+#include <fstream>
+#include <string>
+
+using namespace std;
+
+// 学生信息结构体
+struct Student {
+    string name;
+    int id;
+    float score;
+};
+
+const int MAX_STUDENTS = 100;
+Student students[MAX_STUDENTS];
+int numStudents = 0; // 实际学生数量
+
+// 函数声明
+void displayMenu();
+void inputData();
+void modifyData();
+void deleteData();
+void viewStatistics();
+void saveToFile();
+void readFromFile();
+
+int main() {
+    readFromFile(); // 启动时读取文件中的数据
+
+    int choice;
+    do {
+        displayMenu();
+        cin >> choice;
+        switch(choice) {
+            case 1:
+                inputData();
+                break;
+            case 2:
+                modifyData();
+                break;
+            case 3:
+                deleteData();
+                break;
+            case 4:
+                viewStatistics();
+                break;
+            case 5:
+                saveToFile();
+                break;
+            case 6:
+                cout << "Exiting the program...\n";
+                break;
+            default:
+                cout << "Invalid choice. Please enter again.\n";
+        }
+    } while(choice != 6);
+
+    return 0;
+}
+
+// 显示菜单
+void displayMenu() {
+    cout << "\n===== Student Grade Management System =====\n";
+    cout << "1. Input Student Data\n";
+    cout << "2. Modify Student Data\n";
+    cout << "3. Delete Student Data\n";
+    cout << "4. View Statistics\n";
+    cout << "5. Save Data to File\n";
+    cout << "6. Exit\n";
+    cout << "Enter your choice: ";
+}
+
+// 数据录入
+void inputData() {
+    if (numStudents >= MAX_STUDENTS) {
+        cout << "Cannot add more students. Array is full.\n";
+        return;
+    }
+
+    Student newStudent;
+    cout << "Enter student name: ";
+    cin >> newStudent.name;
+    cout << "Enter student ID: ";
+    cin >> newStudent.id;
+    cout << "Enter student score: ";
+    cin >> newStudent.score;
+
+    // 在这里可以添加数据有效性检查
+
+    students[numStudents++] = newStudent;
+}
+
+// 数据修改
+void modifyData() {
+    int index;
+    cout << "Enter the index of student to modify (0-" << numStudents-1 << "): ";
+    cin >> index;
+
+    if (index >= 0 && index < numStudents) {
+        cout << "Enter new score for " << students[index].name << ": ";
+        cin >> students[index].score;
+    } else {
+        cout << "Invalid index.\n";
+    }
+}
+
+// 数据删除
+void deleteData() {
+    int index;
+    cout << "Enter the index of student to delete (0-" << numStudents-1 << "): ";
+    cin >> index;
+
+    if (index >= 0 && index < numStudents) {
+        for (int i = index; i < numStudents - 1; ++i) {
+            students[i] = students[i + 1];
+        }
+        numStudents--;
+        cout << "Student data deleted.\n";
+    } else {
+        cout << "Invalid index.\n";
+    }
+}
+
+// 查看统计信息
+void viewStatistics() {
+    if (numStudents == 0) {
+        cout << "No students data available.\n";
+        return;
+    }
+
+    float sum = 0, highest = students[0].score, lowest = students[0].score;
+    for (int i = 0; i < numStudents; ++i) {
+        sum += students[i].score;
+        if (students[i].score > highest) {
+            highest = students[i].score;
+        }
+        if (students[i].score < lowest) {
+            lowest = students[i].score;
+        }
+    }
+    float average = sum / numStudents;
+
+    cout << "Statistics:\n";
+    cout << "Number of students: " << numStudents << "\n";
+    cout << "Highest score: " << highest << "\n";
+    cout << "Lowest score: " << lowest << "\n";
+    cout << "Average score: " << average << "\n";
+}
+
+// 将数据保存至文件
+void saveToFile() {
+    ofstream outFile("students.txt");
+    if (!outFile) {
+        cerr << "Error opening file for writing.\n";
+        return;
+    }
+
+    for (int i = 0; i < numStudents; ++i) {
+        outFile << students[i].name << " " << students[i].id << " " << students[i].score << "\n";
+    }
+
+    outFile.close();
+    cout << "Data saved to file successfully.\n";
+}
+
+// 从文件中读取数据
+void readFromFile() {
+    ifstream inFile("students.txt");
+    if (!inFile) {
+        cout << "No previous data found. Starting with an empty database.\n";
+        return;
+    }
+
+    numStudents = 0;
+    while (inFile >> students[numStudents].name >> students[numStudents].id >> students[numStudents].score) {
+        numStudents++;
+    }
+
+    inFile.close();
+    cout << "Data loaded from file successfully.\n";
+}