ADD file via upload

#includeiostrea.txt

@@ -0,0 +1,251 @@
+#include <iostream>
+#include <fstream> // 文件操作
+#include <string>
+#include <iomanip> // 用于格式化输出
+using namespace std;
+
+const int MAX_STUDENTS = 100; // 最大学生数量
+
+// 学生信息结构体
+struct Student {
+    string name;
+    int scores[5]; // 假设有5门课程
+};
+
+// 全局变量
+Student students[MAX_STUDENTS];
+int numStudents = 0; // 实际学生数量
+
+// 函数声明
+void displayMenu();
+void inputData();
+void modifyData();
+void viewStatistics();
+void saveToFile();
+void readFromFile();
+void printStudents();
+int findStudentIndex(const string& name);
+bool isValidScore(int score);
+
+int main() {
+    int choice;
+    readFromFile(); // 程序启动时读取文件数据
+
+    do {
+        displayMenu();
+        cin >> choice;
+        cin.ignore(); // 忽略换行符
+
+        switch (choice) {
+            case 1:
+                inputData();
+                break;
+            case 2:
+                modifyData();
+                break;
+            case 3:
+                viewStatistics();
+                break;
+            case 4:
+                saveToFile();
+                break;
+            case 5:
+                cout << "Exiting program..." << endl;
+                break;
+            default:
+                cout << "Invalid choice. Please try again." << endl;
+        }
+    } while (choice != 5);
+
+    return 0;
+}
+
+void displayMenu() {
+    cout << "===== Student Grade Management System =====" << endl;
+    cout << "1. Input student grades" << endl;
+    cout << "2. Modify/Delete student grades" << endl;
+    cout << "3. View statistics" << endl;
+    cout << "4. Save data to file" << endl;
+    cout << "5. Exit" << endl;
+    cout << "Enter your choice: ";
+}
+
+void inputData() {
+    if (numStudents >= MAX_STUDENTS) {
+        cout << "Database full. Cannot input more students." << endl;
+        return;
+    }
+
+    Student newStudent;
+    cout << "Enter student name: ";
+    getline(cin, newStudent.name);
+
+    for (int i = 0; i < 5; ++i) {
+        int score;
+        do {
+            cout << "Enter score for Course " << (i + 1) << ": ";
+            cin >> score;
+            cin.ignore(); // 忽略换行符
+
+            if (!isValidScore(score)) {
+                cout << "Invalid score. Please enter a score between 0 and 100." << endl;
+            }
+        } while (!isValidScore(score));
+        newStudent.scores[i] = score;
+    }
+
+    students[numStudents++] = newStudent;
+    cout << "Student data entered successfully." << endl;
+}
+
+void modifyData() {
+    if (numStudents == 0) {
+        cout << "No students in the database." << endl;
+        return;
+    }
+
+    string name;
+    cout << "Enter student name to modify/delete: ";
+    getline(cin, name);
+
+    int index = findStudentIndex(name);
+    if (index == -1) {
+        cout << "Student not found." << endl;
+        return;
+    }
+
+    // 显示学生信息
+    cout << "Student found:" << endl;
+    cout << "Name: " << students[index].name << endl;
+    cout << "Scores:" << endl;
+    for (int i = 0; i < 5; ++i) {
+        cout << "Course " << (i + 1) << ": " << students[index].scores[i] << endl;
+    }
+
+    // 询问用户是否修改或删除
+    int choice;
+    cout << "Do you want to modify (1) or delete (2) this student's data? ";
+    cin >> choice;
+    cin.ignore(); // 忽略换行符
+
+    if (choice == 1) {
+        // 修改数据
+        for (int i = 0; i < 5; ++i) {
+            int score;
+            do {
+                cout << "Enter new score for Course " << (i + 1) << ": ";
+                cin >> score;
+                cin.ignore(); // 忽略换行符
+
+                if (!isValidScore(score)) {
+                    cout << "Invalid score. Please enter a score between 0 and 100." << endl;
+                }
+            } while (!isValidScore(score));
+            students[index].scores[i] = score;
+        }
+        cout << "Student data modified successfully." << endl;
+    } else if (choice == 2) {
+        // 删除数据，将后面的学生数据往前移
+        for (int i = index; i < numStudents - 1; ++i) {
+            students[i] = students[i + 1];
+        }
+        numStudents--;
+        cout << "Student data deleted successfully." << endl;
+    } else {
+        cout << "Invalid choice. No changes made." << endl;
+    }
+}
+
+void viewStatistics() {
+    if (numStudents == 0) {
+        cout << "No students in the database." << endl;
+        return;
+    }
+
+    int minScore = INT_MAX, maxScore = INT_MIN, totalScore = 0;
+
+    for (int i = 0; i < numStudents; ++i) {
+        for (int j = 0; j < 5; ++j) {
+            int score = students[i].scores[j];
+            if (score < minScore) minScore = score;
+            if (score > maxScore) maxScore = score;
+            totalScore += score;
+        }
+    }
+
+    double averageScore = static_cast<double>(totalScore) / (numStudents * 5);
+
+    cout << "===== Statistics =====" << endl;
+    cout << "Number of students: " << numStudents << endl;
+    cout << "Minimum score: " << minScore << endl;
+    cout << "Maximum score: " << maxScore << endl;
+    cout << "Average score: " << fixed << setprecision(2) << averageScore << endl;
+}
+
+void saveToFile() {
+    ofstream outFile("students.txt");
+
+    if (!outFile) {
+        cout << "Error opening file." << endl;
+        return;
+    }
+
+    outFile << numStudents << endl;
+
+    for (int i = 0; i < numStudents; ++i) {
+        outFile << students[i].name << endl;
+        for (int j = 0; j < 5; ++j) {
+            outFile << students[i].scores[j] << " ";
+        }
+        outFile << endl;
+    }
+
+    outFile.close();
+    cout << "Data saved to file successfully." << endl;
+}
+
+void readFromFile() {
+    ifstream inFile("students.txt");
+
+    if (!inFile) {
+        cout << "File not found. Starting with an empty database." << endl;
+        return;
+    }
+
+    inFile >> numStudents;
+    inFile.ignore(); // 忽略换行符
+
+    for (int i = 0; i < numStudents; ++i) {
+        getline(inFile, students[i].name);
+        for (int j = 0; j < 5; ++j) {
+            inFile >> students[i].scores[j];
+        }
+        inFile.ignore(); // 忽略换行符
+    }
+
+    inFile.close();
+    cout << "Data loaded from file successfully." << endl;
+}
+
+void printStudents() {
+    cout << "===== Student List =====" << endl;
+    for (int i = 0; i < numStudents; ++i) {
+        cout << "Student " << (i + 1) << ": " << students[i].name << endl;
+        for (int j = 0; j < 5; ++j) {
+            cout << "  Course " << (j + 1) << ": " << students[i].scores[j] << endl;
+        }
+    }
+}
+
+int findStudentIndex(const string& name) {
+    for (int i = 0; i < numStudents; ++i) {
+        if (students[i].name == name) {
+            return i;
+        }
+    }
+    return -1;
+}
+
+bool isValidScore(int score) {
+    return (score >= 0 && score <= 100);
+}