C++ 重载运算符>>(输入)不会更改原始运算符

我正在尝试使用自定义字符串和定义类构建一个自定义字典类。在尝试重载>>（输入）时，我遇到了某种问题。当函数结束时，发送到它的字典不会改变。附加代码：这是重载：

istream& operator>>(istream& ip, Dictionary& var) {
    Definition temp;
    ip >> temp;
    var += temp;
    return ip;
}

以及其中使用的其他一些功能：

Dictionary& Dictionary::operator+=(Definition& input) {
    if (!checkCopy(input))
    {
        Definition** temp;
        temp = new Definition*[numWords + 1];
        for (int i = 0; i < numWords; i++)
        {
            temp[i] = book[i];
        }
        numWords++;
        temp[numWords - 1] = &input;
        delete[] book;
        book = temp;
    }
    return *this;
}
Dictionary::Dictionary(Dictionary& input) {
    *this = input;
}
Dictionary& Dictionary::operator=(Dictionary& input) {
    if (numWords != 0)
        delete[] book;
    book = new Definition*[input.numWords];
    for (int i = 0; i < input.numWords; i++)
    {
        *this += *input.book[i];
    }
    return *this;
}

以及类本身：

class Dictionary
{
private:
    int numWords = 0;
    Definition** book;
public:
    Dictionary();
    ~Dictionary();
    Dictionary(Dictionary&);
    bool operator==(Dictionary&) const;
    Dictionary& operator=(Definition&);
    Dictionary& operator=(Dictionary&);
    friend ostream& operator<<(ostream&, const Dictionary&);
    friend istream& operator>>(istream&, Dictionary&);
    Dictionary& operator-=(int);
    Dictionary& operator+=(Definition&);
    bool checkCopy(Definition&);
    Definition& operator[](int); //left side brackets for input
    Definition operator[](int) const; //right side brackets for output
};

编辑：这里也是定义输入的重载运算符：

istream& operator>>(istream& ip, Definition& var)
{
    cout << "Please enter a word: " << endl;
    ip >> var.word;
    cout << "Please enter the number of definitions for this word: " << endl;
    int idx;
    cin >> idx;
    while (idx<0)
    {
        cout << "Error: number of definitions not possible. Please Try again: " << endl;
        cin.clear();
        cin.ignore(INT_MAX, 'n');
        cin >> idx;
    }
    cin.clear();
    cin.ignore(INT_MAX, 'n');
    String* temp = new String[idx];
    for (int i = 0; i < idx; i++) {
        cout << "Please enter the " << i + 1 << "th definition: " << endl;
        cin >> temp[i];
        var += temp[i];
    }
    var.sortDefinition();
    return ip;
}

确实需要帮助。