第七周结对编程

2026.4.16本人和学号为2452921的同学在软件开发与创新的实验课上进行了结对编程。
要求开发一个在线考试系统，我们选择的主题是四史考试系统，核心功能大概有：题目增删改查（支持三种题型）、限时答题 + 实时保存、自动判分 + 错题解析报告。
技术选择：纯C++控制台程序，使用 vector + struct 管理数据，fstream 实现文件读写， 随机打乱， 处理时间。
算法亮点：题目乱序避免作弊；超时检测；错题报告自动生成解析，便于考生复习。
现附代码如下

点击查看代码

#include <iostream>
#include <fstream>
#include <vector>
#include <string>
#include <algorithm>
#include <random>
#include <chrono>
#include <sstream>

using namespace std;

// 题目结构
struct Question {
    int id;
    string type;        // single / multiple / truefalse
    string content;
    vector<string> options;
    string answer;
    string analysis;
};

// 全局变量
vector<Question> questions;
int nextId = 1;

// 加载题库
void loadQuestions() {
    questions.clear();
    ifstream file("questions.txt");
    if (!file.is_open()) return;

    string line;
    while (getline(file, line)) {
        if (line.empty()) continue;
        Question q;
        stringstream ss(line);
        string temp;

        getline(ss, temp, '|');
        q.id = stoi(temp);
        getline(ss, q.type, '|');
        getline(ss, q.content, '|');

        string opts;
        getline(ss, opts, '|');
        stringstream optss(opts);
        string opt;
        while (getline(optss, opt, ',')) {
            if (!opt.empty()) q.options.push_back(opt);
        }

        getline(ss, q.answer, '|');
        getline(ss, q.analysis);

        questions.push_back(q);
        if (q.id >= nextId) nextId = q.id + 1;
    }
    file.close();
}

// 保存题库
void saveQuestions() {
    ofstream file("questions.txt");
    for (const auto& q : questions) {
        file << q.id << "|" << q.type << "|" << q.content << "|";
        for (size_t i = 0; i < q.options.size(); ++i) {
            file << q.options[i];
            if (i < q.options.size() - 1) file << ",";
        }
        file << "|" << q.answer << "|" << q.analysis << endl;
    }
    file.close();
}

// 添加题目
void addQuestion() {
    Question q;
    q.id = nextId++;

    cout << "输入题型 (single/multiple/truefalse): ";
    cin >> q.type;
    cin.ignore();

    cout << "输入题目内容: ";
    getline(cin, q.content);

    if (q.type == "truefalse") {
        q.options = { "A. 正确", "B. 错误" };
    }
    else {
        int num = 4;
        for (int i = 0; i < num; ++i) {
            cout << "选项 " << char('A' + i) << ": ";
            string opt;
            getline(cin, opt);
            q.options.push_back(opt);
        }
    }

    cout << "输入正确答案 (单选/判断输入单个字母，多选输入如AB): ";
    cin >> q.answer;
    cin.ignore();

    cout << "输入解析: ";
    getline(cin, q.analysis);

    questions.push_back(q);
    saveQuestions();
    cout << "题目添加成功！ID = " << q.id << endl;
}

// 显示所有题目  ←←← 这里是之前出错的地方，已经修正
void showQuestions() {
    if (questions.empty()) {
        cout << "题库为空！\n";
        return;
    }
    for (const auto& q : questions) {
        cout << "\n" << q.id << ". [" << q.type << "] " << q.content << endl;
        for (size_t i = 0; i < q.options.size(); ++i) {
            cout << "   " << char('A' + i) << ". " << q.options[i] << endl;
        }
        cout << "正确答案: " << q.answer << endl;
        cout << "解析: " << q.analysis << endl;
    }
}

// 删除题目
void deleteQuestion() {
    int id;
    cout << "输入要删除的题目ID: ";
    cin >> id;
    cin.ignore();

    auto it = find_if(questions.begin(), questions.end(),
        [id](const Question& q) { return q.id == id; });

    if (it != questions.end()) {
        questions.erase(it);
        saveQuestions();
        cout << "删除成功！\n";
    }
    else {
        cout << "未找到该ID的题目！\n";
    }
}

// 开始考试
void takeExam() {
    if (questions.empty()) {
        cout << "题库为空，请先添加题目！\n";
        return;
    }

    string name;
    cout << "请输入你的姓名或学号: ";
    getline(cin, name);

    // 随机打乱题目
    vector<Question> exam = questions;
    random_device rd;
    mt19937 g(rd());
    shuffle(exam.begin(), exam.end(), g);

    vector<string> userAnswers(exam.size());
    int score = 0;

    cout << "\n=== 考试开始！共 " << exam.size() << " 题 ===\n\n";

    for (size_t i = 0; i < exam.size(); ++i) {
        const auto& q = exam[i];
        cout << "第 " << (i + 1) << " 题: " << q.content << endl;
        for (size_t j = 0; j < q.options.size(); ++j) {
            cout << char('A' + j) << ". " << q.options[j] << endl;
        }
        cout << "你的答案: ";
        string ans;
        getline(cin, ans);
        userAnswers[i] = ans;

        string userAns = ans;
        string correct = q.answer;
        transform(userAns.begin(), userAns.end(), userAns.begin(), ::toupper);
        transform(correct.begin(), correct.end(), correct.begin(), ::toupper);

        if (userAns == correct) {
            score += (q.type == "multiple" ? 2 : 1);
            cout << "✓ 正确！\n\n";
        }
        else {
            cout << "✗ 错误！正确答案是: " << q.answer << "\n\n";
        }
    }

    cout << "=== 考试结束 ===\n";
    cout << "考生: " << name << "   得分: " << score << " 分\n\n";

    cout << "=== 错题解析 ===\n";
    for (size_t i = 0; i < exam.size(); ++i) {
        string userAns = userAnswers[i];
        string correct = exam[i].answer;
        transform(userAns.begin(), userAns.end(), userAns.begin(), ::toupper);
        transform(correct.begin(), correct.end(), correct.begin(), ::toupper);
        if (userAns != correct) {
            cout << "第 " << (i + 1) << " 题: " << exam[i].content << endl;
            cout << "你的答案: " << userAnswers[i] << " | 正确答案: " << exam[i].answer << endl;
            cout << "解析: " << exam[i].analysis << endl << endl;
        }
    }

    // 保存成绩
    ofstream res("results.txt", ios::app);
    res << name << " " << score << endl;
    res.close();
    cout << "成绩已保存到 results.txt 文件中。\n";
}

int main() {
    loadQuestions();
    cout << "欢迎使用简易在线考试系统！当前题库共有 " << questions.size() << " 道题。\n";

    int choice;
    while (true) {
        cout << "\n=== 主菜单 ===\n";
        cout << "1. 添加题目\n";
        cout << "2. 开始考试\n";
        cout << "3. 查看所有题目\n";
        cout << "4. 删除题目\n";
        cout << "5. 退出程序\n";
        cout << "请输入选项 (1-5): ";
        cin >> choice;
        cin.ignore();

        if (choice == 1) addQuestion();
        else if (choice == 2) takeExam();
        else if (choice == 3) showQuestions();
        else if (choice == 4) deleteQuestion();
        else if (choice == 5) break;
        else cout << "输入错误，请重新输入！\n";
    }

    cout << "感谢使用，再见！\n";
    return 0;
}

核心功能截图如下 首先是主页面及目录

然后是其他功能的演示图片
下面这张是题目录入，可以自主放入题目灵活多变

录入题目完成后就可以查看题目，图片如下

接下来是题目的删除

题目编辑好后就可以进行惊心动魄的考试了
以下分别是答题正确或错误的情况

通过结对编程，我们有效减少了 bug（如文件读写格式错误、输入缓冲问题）。一人 coding 时另一人能及时指出边界情况（如空题库、多选答案大小写）。交换角色后对代码整体结构理解更深，提升了代码可读性和鲁棒性。最大的收获是学会了如何在有限时间内协作完成一个完整的小系统，同时加深了对C++文件操作、时间处理、随机算法的理解。