Question

我目前正在用C ++开展一个测验项目，我对如何使其中的一些工作感到困惑。我有一个课程（测验），它设置了测验如何工作的规则。它看起来像这样：

class quiz
{
private:
    //how many questions
    int num_q;
    char answer[50];
    string question[50];

    int pom;
    string plus;
    string minus;

public:
    quiz()
    {
        pom = 0;
    }
    void set_pom_answers(string pluss, string minuss)
    {
        plus = pluss;
        minus = minuss;
    }
    void set_num_q(int num_qq)
    {
        num_q = num_qq;
    }
    //Question_Number = question number, ca = correct answer, and q = question
    void set_q_a(int Question_Number, string q, char ca)
    {
        question[Question_Number - 1] = q;
        answer[Question_Number - 1] = ca;
    }
    void run_quiz()
    {
        char ans;
        for (int i = 0; i < num_q; i++)
        {
            cout << question[i] << ": ";
            cin >> ans;
            if (ans == answer[i])
            {
                cout << "Correct! good for you!" << endl;
                pom = pom + 1;
            }
            else
            {
                cout << "Wrong. :(" << endl;
                pom = pom;

            }
            system("pause");
            system("cls");
        }
        if (pom >= (num_q / 2))
        {
            cout << plus << endl;
            cout << "your score was " << pom << endl;
        }
        else if (pom < (num_q / 2))
        {
            cout << minus << endl;
            cout << "your score was " << pom << endl;
        }
        else
        {
            cout << "input not recognised" << endl;
        }
        system("pause");
    }

};

要使用此操作运行测验，请在Main（）中使用这样的格式：

        quiz Politics;
        Politics.set_num_q(10);
        Politics.set_pom_answers("You're good at Politics.", "Revise more!");
        Politics.set_q_a(1, "Michael Fallon is the current foreign secretary: [t]rue or [f]alse", 'f');
        Politics.set_q_a(2, "Tony Blair was PM from 1996-2007: [t]rue or [f]alse", 'f');
        Politics.set_q_a(3, "Michael Gove is the current education secretary : [t]rue or [f]alse", 'f');
        Politics.set_q_a(4, "Teresa May is the current home secretary: [t]rue or [f]alse", 't');
        Politics.set_q_a(5, "Owen Jones is a blairite: [t]rue or [f]alse", 'f');
        Politics.set_q_a(6, "Nick Robinson is the BBC's political editor: [t]rue or [f]alse", 'f');
        Politics.set_q_a(7, "David Cameron is a eurosceptic: [t]rue or [f]alse", 't');
        Politics.set_q_a(8, "Matthew Handcock is a Tory MP: [t]rue or [f]alse", 't');
        Politics.set_q_a(9, "Jonathon Woodcock is a Labour MP: [t]rue or [f]alse", 't');
        Politics.set_q_a(10, "David McDonell is the current shadow chancellor: [t]rue or [f]alse", 'f');

当我使用Politics.run_quiz（）运行它时，上述工作绝对正常。

问题在于我想创建一个菜单，允许我制作或参加测验，而我对如何编码制作者部分感到困惑。最后，我想将此信息保存到文件中，当用户在菜单中选择“take”时，他们将加载此文件并从中运行测验。到目前为止，我只是作为一个例子来说明我想要的东西：

int main()
    {

        int Choice;

        do {
            cout << "Would you like to:\n\n" << "1)Make a quiz?\n" << "2) Take a quiz?\n" << "3) Quit?\n\n";
            cin >> Choice;
        } while (Choice > 3);       

        if (Choice == 1) {
            string Quiz_Name;
            cout << "What is the name of this quiz?\n";
            cin >> Quiz_Name;

            int Num_of_Qs;
            cout << "How many Questions should there be?\n";
            cin >> Num_of_Qs;

            string Answer_Plus;
            cout << "What message should be displayed if the score is above 50%?\n";
            cin >> Answer_Plus;

            string Answer_Minus;
            cout << "What message should be displayed if the score is less that 50%?\n";
            cin >> Answer_Minus;

            /*Here I would like to add all the elements together, along with the questions and answers. for example:

            quiz Quiz_Name;
            Quiz_Name.set_num_q(Num_of_Qs);
            Quiz_Name.set_pom_answers(Answer_Plus, Answer_Minus);

            for (int j = 1; j <= Num_of_Qs; j++) {
            Quiz_Name.set_q_a(j, [The user inputs a question], [the user inputs an answer])
            }

            or something along those lines? How would I make something like this work?

            */


        }

        if (Choice == 2) {
            Politics.run_quiz();
        }

        if (Choice == 3) {
            return 0;
        }

    }

我不知道这是否是最佳方式？有人可以帮我解决如何使用用户输入进行测验吗？

谢谢！

Answer 1

这是一个非常好的方法。据我所知，这是“最好”的做法（如果我错了，有人会纠正我）。

请记住，您不应该使用cin >> str，因为它会在（空格）处停止。 getline(cin, str)停在\n，这是您想要的，因为输入可以包含空格。

Answer 2

TL; DR。

我建议使用具有问题和答案的结构：

class Question_Answer
{
  std::string  question;
  std::string  answer;
};

你的测验将是容器的问题和答案：

typedef std::vector<Question_Answer> Quiz_Container;
Quiz_Container politics_quiz;

您可以重载流提取operator>>以使对象从流（即文件）中读取其成员：

class Question_Answer
{
  std::string question;
  std::string answer;
  friend std::istream& operator>>(std::istream& input, 
                                  Question_Answer& qa);
};
std::istream& operator>>(std::istream& input,
                         Question_Answer& qa)
{
  std::getline(input, question);
  std::getline(input, answer);
  return input;
}

输入循环可以实现为：

Question_Answer quiz_element;
Quiz            politics_quiz;
while (politic_questions_file >> quiz_element)
{
  politics_quiz.push_back(quiz_element);
}

这可以扩展，以便问题可以有选择和答案选择：

class Question_Answer
{
  std::string  question;
  std::vector<std::string> choices;
  unsigned int answer_choice;
};

提出的概念：

测验元素是问答对（或类似）。
测验是测验元素的容器。
重载流提取operator>>允许测验元素从流中读取自己的成员。流可以是一个文本文件。

如何在我的C ++测验中输入问题？

2 个答案: