C++：來自外部文件的瑣事

Question

我有這個代碼，它工作正常。 我需要包括以“？”分隔的問題和答案在一個外部文本文件中，我需要一些幫助。

現在我有以下問題和答案：

trivia.setQuestion("Who is the patron saint of Ireland?");
        trivia.setAnswer("St. Patrick");
        trivia.setAmount(2);
        triviaList.push_back(trivia);

        trivia.setQuestion("Name Batman’s crime fighting partner?");
        trivia.setAnswer("Robin");
        trivia.setAmount(10);
        triviaList.push_back(trivia);

        trivia.setQuestion("What is the name of Peppa Pig’s brother?");
        trivia.setAnswer("George");
        trivia.setAmount(5);
        triviaList.push_back(trivia);

編輯：我想將問題傳遞給 setQuestion()，並將答案傳遞給 setAnswer()

trivia.text
Who is the patron saint of Ireland? St. Patrick
Name Batman’s crime fighting partner? Robin
What is the name of Peppa Pig’s brother? George

我知道我需要實現這一點：

string line;
cout << "Enter input: ";
getline(cin, line, "?");

當然還可以打開和關閉 trivia.text，但是我如何像本地人一樣提出問題和答案？

任何幫助將不勝感激，提前致謝！！

#include <iostream>
#include <string>
#include <fstream>
#include <vector>
using namespace std;
class TriviaGame {

public:
    TriviaGame();
    TriviaGame(string question, string answer, int amount);
    ~TriviaGame() {};
    string getQuestion();
    void setQuestion(string newQuestion);
    string getAnswer();
    void setAnswer(string newAnswer);
    int getAmount();
    void setAmount(int newAmount);

private:
    string question;
    string answer;
    int amount;
};

TriviaGame::TriviaGame() {
    question = "";
    answer = "";
    amount = 0;
}

TriviaGame::TriviaGame(string question, string answer, int amount) {
    this->question = question;
    this->answer = answer;
    this->amount = amount;
}

string TriviaGame::getQuestion() {
    return question;
}

void TriviaGame::setQuestion(string newQuestion) {
    question = newQuestion;
}

string TriviaGame::getAnswer() {
    return answer;
}

void TriviaGame::setAnswer(string newAnswer) {
    answer = newAnswer;
}

int TriviaGame::getAmount() {
    return amount;
}

void TriviaGame::setAmount(int newAmount) {
    amount = newAmount;
}

    // main function
int main() {
    vector<TriviaGame> triviaList;
    TriviaGame trivia;

    // === Input Stream ===
    fstream inputStream;
    inputStream.open("trivia.txt");
    if(!inputStream.is_open()) {
        cout << "File not found!\n";
        exit(0);
    }
    else {
        string line;

   // while(getline(inputStream, line, "?")){
        while(getline( inputStream, line, '?')) {

trivia.setQuestion(line);
trivia.setAnswer("St. Patrick");
trivia.setAmount(2);
triviaList.push_back(trivia);

trivia.setQuestion(line);
trivia.setAnswer("Robin");
trivia.setAmount(10);
triviaList.push_back(trivia);

trivia.setQuestion(line);
trivia.setAnswer("George");
trivia.setAmount(5);
triviaList.push_back(trivia);
    int winnings = 0;
    cout << "Trivia Game!" << endl;
    for (int i=0; i < triviaList.size(); i++)
    {
        cout << "You have $" << winnings << endl;
        cout << triviaList[i].getQuestion() << endl;
        string answer;
        getline(cin, answer);
        if (answer == triviaList[i].getAnswer())
        {
            cout << "That's right!  You win $" <<
            triviaList[i].getAmount() << endl;
            winnings += triviaList[i].getAmount();
        }
        else
        {
            cout << "Sorry, the correct answer is: " <<
            triviaList[i].getAnswer() << endl;
        }
    }
    cout << "Game over.  Your total winnings are: $" << winnings;

    cout << endl;
}

Answer 1

你已經意識到你需要做什么：

getline(cin, line, "?");

您只需要查看std::getline詳細信息並發現它應該采用char ，而不是const char* （都不是std::string ）作為分隔符。 只需替換"?" 用'?' .

我准備了一個簡短的例子，你如何使用它：

int main() {
    std::istringstream input{"The question? The answer.\n"
                             "Another question? Another answer.\n"
                             "What is 2+2? Definitely 4.\n"};

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

    while(std::getline(input, question, '?') &&
          std::getline(input, answer)) {
        std::cout << "Q: " << question << " A: " << answer << '\n';
    }
}

在上面的例子中，你有兩個std::string s - 一個保存問題，另一個保存答案。

不要忘記為std::istringstream #include <sstream> 。 如果您不知道std::istringstream是什么，您可以單擊上面的鏈接，或者std::istringstream假設它只是一個“硬編碼的std::cin ”。 它的行為類似於輸入流（就像std::cin ），但可以使用const char*或std::string進行初始化。

要讓您的代碼改用標准輸入，只需刪除std::istringstream部分並將input替換為std::cin 。

要使您的代碼與文本文件一起使用，請閱讀std::ifstream1 。 它的行為非常像std::cin （因為它們都是輸入流）。 創建std::ifstream對象，將其命名為input （或您喜歡的任何名稱）並像對待std::cin一樣對待它。