Variadic Template（六）

利用递归继承的方式实现tuple

 

#include<iostream>
using namespace std;

template<typename... Values> class tuples;
template<> class tuples<>{};

template<typename Head, typename... Tail>
class tuples<Head, Tail...> : private tuples<Tail...>
{
    typedef tuples<Tail...> inherited;
protected:

    Head m_head;
public:
    tuples();
    tuples(Head v, Tail... vtail) : m_head(v), inherited(vtail...){}

    auto head()->decltype(m_head) {
        return m_head;
    }
    inherited& tail(){
        return *this;
    }
};

int main()
{
    tuples<int,float,string>t(41,6.3,"nico");
    cout << "sizeof(t) : " << sizeof(t) << endl;
    cout << t.head() << endl;
    cout << t.tail().head() << endl;
    cout << t.tail().tail().head() << endl;
    return 0;
}

 

问题1：sizeof(t)为什么是40呢？视频里说是12