Variadic Templates（二） -实现 tuple

约定不等于承诺〃 2024-04-17 17:01 55阅读 0赞

本文用两种方法模拟实现c++中的Tuple。

Tuple可以接收任意数量和类型的元素。

测试代码如下：

#include <iostream>
    #include <string>
    int main()
    {
        tuple<int, float, std::string> t(10, 9.17, "April");
        std::cout << t.GetHead() << std::endl;
        std::cout << t.GetTail().GetHead() << std::endl;
        std::cout << t.GetTail().GetTail().GetHead() << std::endl;
    }

**1.继承方式实现tuple**

template<typename... Values> class tuple;
    template<> class tuple<> {};
    
    template<typename Head, typename... Tail>
    class tuple<Head, Tail...> :private tuple<Tail...>
    {
    public:
        tuple() {}
        tuple(Head head, Tail... tail):m_Head(head), tuple<Tail...>(tail...) {}
    
        Head GetHead() { return m_Head; }
        tuple<Tail...>& GetTail() { return *this; }
    protected:
        Head m_Head;
    };

测试代码运行结果：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2xpeWF6aGVuMjAxMQ_size_16_color_FFFFFF_t_70][]

**2.组合方式实现tuple**

template<typename... Values> class tuple;
    template<> class tuple<> {};
    
    template<typename Head, typename... Tail>
    class tuple<Head, Tail...>
    {
    public:
        tuple() {}
        tuple(Head head, Tail... tail):m_Head(head), m_Tail(tail...) {}
        Head GetHead() { return m_Head; }
        tuple<Tail...>& GetTail() { return m_Tail; }
    protected:  
        Head m_Head;
        tuple<Tail...> m_Tail;
    };

测试代码运行结果：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2xpeWF6aGVuMjAxMQ_size_16_color_FFFFFF_t_70 1][]

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2xpeWF6aGVuMjAxMQ_size_16_color_FFFFFF_t_70]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/17/f595520d1fe64ed4afb6a97af55aa150.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2xpeWF6aGVuMjAxMQ_size_16_color_FFFFFF_t_70 1]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/17/839585cf221942589e27c59b2b3828a4.png