Question

我收到以下错误：

Database.hpp: In member function ‘Table<T, S>& Table<T, S>::operator=(const Table<T, S>&) [with T = int, int S = 3, Table<T, S> = Table<int, 3>]’:
Database.hpp:40:8:   instantiated from ‘void std::vector<_Tp, _Alloc>::_M_insert_aux(std::vector<_Tp, _Alloc>::iterator, const _Tp&) [with _Tp = List, _Alloc = std::allocator<List>, std::vector<_Tp, _Alloc>::iterator = __gnu_cxx::__normal_iterator<List*, std::vector<List> >, typename std::_Vector_base<_Tp, _Alloc>::_Tp_alloc_type::pointer = List*]’
/usr/include/c++/4.6/bits/stl_vector.h:834:4:   instantiated from ‘void std::vector<_Tp, _Alloc>::push_back(const value_type&) [with _Tp = List, _Alloc = std::allocator<List>, std::vector<_Tp, _Alloc>::value_type = List]’
SelectiveReading.hpp:139:34:   instantiated from here
Database.hpp:34:16: error: invalid initialization of non-const reference of type ‘Table<int, 3>&’ from an rvalue of type ‘Table<int, 3>* const’

我有以下ADT。我不明白它们有什么问题。

// this is Database.hpp
template <class T, int S>
class Table
{
    T tab[S];
    public:
    inline T& operator[](int i)
    {
        return tab[i];
    }
    inline const T& operator[](int i) const
    {
        return tab[i];
    }
    Table() {}
    ~Table() {}
    Table(const Table &t)
    {
        for ( int i=0; i<S; ++i )
        {
            tab[i] = t[i];
        }
    }
    Table& operator=(const Table &t)
    {
        for ( int i=0; i<S; ++i )
        {
            tab[i] = t[i];
        }
        return this;
    }
};

typedef Table<int,3> Date;

struct List
{
    Date AnnouncementDate;
    int BonusShares;
    int StockSplit;
    int CashDividend;
    bool DividendPayment;
    Date ExDividendDate;
    Date ShareRecordDate;
    Date BonusSharesListingDate;
};

typedef std::vector<List> Database;

虽然电话是这样的：

List record;
// (...)
Data.push_back(record); // this is SelectiveReading.hpp:139:34

Answer 1

在operator=的最后一行，当您打算返回this（参考）时，您将返回*this（指针）。

Answer 2

return this;必须为return *this;

使用模板时奇怪的“非const引用的无效初始化”

2 个答案: