如何在堆栈上向对象数组添加对象？

Question

我目前正在创建一个帮助我学习新词汇的程序。该程序的工作流程将由VocabularyTester类统治，它包含存储在矢量数组中的WordPair类对象列表。

class VocabularyTester
{
private:
    std::vector<WordPair> wordList;
    std::vector<WordPair> failedPairs;
    std::vector<WordPair> passedPairs;
    WordPair recentPair;

public:
    VocabularyTester();
    void run();
    void loadWordList(std::wstring& vocabularyRaw);
    /*
     other parts of the code
    */
};

/* the function i'm having a problem with */
void VocabularyTester::loadWordList(std::wstring& vocabularyRaw)
{
    std::wstring rawPair;
    unsigned int iterator = 0, prevIterator = 0;

    for (;;)
    {
        iterator = vocabularyRaw.find(L"\r\n", iterator);

        if (iterator == std::string::npos)
        {
            break;
        }

        rawPair = vocabularyRaw.substr(prevIterator, iterator);
        wordList.emplace_back(rawPair); /*there occurs the read access violation exception*/
        prevIterator = iterator;
    }
}

当执行到达wordList.emplace_back（rawPair）时，抛出读取访问冲突异常，正好在这里：

/* vector header file */
bool _Has_unused_capacity() const _NOEXCEPT
        {   // micro-optimization for capacity() != size()
        return (this->_Myend() != this->_Mylast());
        }

WordPair是一对2个单词，它有2个字符串成员：leftWord用于母语单词，rightWord用于某个单词想要学习的单词。这是我用来将它添加到矢量数组的对象的构造函数：

WordPair::WordPair(std::wstring& rawPair)
{
    std::wstring separator = L" - ";
    size_t separatorPosition = rawPair.find(separator);
    std::wstring leftWord = rawPair.substr(0, separatorPosition);
    std::wstring rightWord = rawPair.substr(separatorPosition + separator.length());
    this->leftWord = leftWord;
    this->rightWord = rightWord;
}

感谢您的帮助。