写一个能够读取文件的学生学籍管理立体

为了实现一个能够读取文件的学生学籍管理系统，我们需要实现以下功能：

1. 学生信息数据结构
2. 读取学生信息文件
3. 显示学生信息
4. 添加学生信息
5. 删除学生信息
6. 修改学生信息
7. 保存学生信息到文件中
8. 退出程序

下面是一个基本的实现：

#include <iostream>
#include <fstream>
#include <vector>
#include <string>

// 学生信息数据结构
struct Student {
    std::string name;
    int age;
    std::string gender;
    std::string major;
    std::string id;
};

// 读取学生信息文件
std::vector<Student> readStudentsFromFile(const std::string& filename) {
    std::vector<Student> students;
    std::ifstream infile(filename);

    std::string line;
    while (std::getline(infile, line)) {
        std::istringstream iss(line);
        std::string name, gender, major, id;
        int age;
        if (iss >> name >> age >> gender >> major >> id) {
            students.push_back({name, age, gender, major, id});
        }
    }

    infile.close();
    return students;
}

// 显示学生信息
void displayStudents(const std::vector<Student>& students) {
    for (const auto& student : students) {
        std::cout << "Name: " << student.name << std::endl;
        std::cout << "Age: " << student.age << std::endl;
        std::cout << "Gender: " << student.gender << std::endl;
        std::cout << "Major: " << student.major << std::endl;
        std::cout << "ID: " << student.id << std::endl;
        std::cout << std::endl;
    }
}

// 添加学生信息
void addStudent(std::vector<Student>& students) {
    std::cout << "Please enter the student's information:" << std::endl;
    std::string name, gender, major, id;
    int age;
    std::cout << "Name: ";
    std::cin >> name;
    std::cout << "Age: ";
    std::cin >> age;
    std::cout << "Gender: ";
    std::cin >> gender;
    std::cout << "Major: ";
    std::cin >> major;
    std::cout << "ID: ";
    std::cin >> id;
    students.push_back({name, age, gender, major, id});
    std::cout << "Student added successfully!" << std::endl;
}

// 删除学生信息
void deleteStudent(std::vector<Student>& students) {
    std::string id;
    std::cout << "Please enter the student's ID you want to delete: ";
    std::cin >> id;

    auto it = std::find_if(students.begin(), students.end(), [&id](const Student& student) {
        return student.id == id;
    });

    if (it != students.end()) {
        students.erase(it);
        std::cout << "Student deleted successfully!" << std::endl;
    } else {
        std::cout << "No student with ID " << id << " found." << std::endl;
    }
}

// 修改学生信息
void modifyStudent(std::vector<Student>& students) {
    std::string id;
    std::cout << "Please enter the student's ID you want to modify: ";
    std::cin >> id;

    auto it = std::find_if(students.begin(), students.end(), [&id](const Student& student) {
        return student.id == id;
    });

    if (it != students.end()) {
        std::cout << "Please enter the new information:" << std::endl;
        std::cout << "Name: ";
        std::cin >> it->name;
        std::cout << "Age: ";
        std::cin >> it->age;
        std::cout << "Gender: ";
        std::cin >> it->gender;
        std::cout << "Major: ";
        std::cin >> it->major;
        std::cout << "ID: ";
        std::cin >> it->id;
        std::cout << "Student modified successfully!" << std::endl;
    } else {
        std::cout << "No student with ID " << id << " found." << std::endl;
    }
}

// 保存学生信息到文件中
void saveStudentsToFile(const std::vector<Student>& students, const std::string& filename) {
    std::ofstream outfile(filename);

    for (const auto& student : students) {
        outfile << student.name << " "
                << student.age << " "
                << student.gender << " "
                << student.major << " "
                << student.id << std::endl;
    }

    outfile.close();
    std::cout << "Students saved to file successfully!" << std::endl;
}

int main() {
    std::string filename = "students.txt";
    std::vector<Student> students = readStudentsFromFile(filename);

    while (true) {
        std::cout << "Please select an operation:" << std::endl;
        std::cout << "1. Display all students" << std::endl;
        std::cout << "2. Add a student" << std::endl;
        std::cout << "3. Delete a student" << std::endl;
        std::cout << "4. Modify a student" << std::endl;
        std::cout << "5. Save students to file" << std::endl;
        std::cout << "6. Exit" << std::endl;

        int choice;
        std::cin >> choice;

        switch (choice) {
            case 1:
                displayStudents(students);
                break;
            case 2:
                addStudent(students);
                break;
            case 3:
                deleteStudent(students);
                break;
            case 4:
                modifyStudent(students);
                break;
            case 5:
                saveStudentsToFile(students, filename);
                break;
            case 6:
                return 0;
            default:
                std::cout << "Invalid choice." << std::endl;
        }
    }
}

在这个程序中，我们通过`readStudentsFromFile`函数读取学生信息文件，使用`displayStudents`函数显示学生信息，使用`addStudent`、`deleteStudent`、`modifyStudent`函数进行学生信息的添加、删除和修改，使用`saveStudentsToFile`函数将学生信息保存到文件中。我们使用`while`循环不断接收用户输入，根据用户的选择调用相应的操作函数。