operator << - 如何检测最后一个参数

ostream& operator<<(ostream& os, const T& obj)
{
    // 将对象的内容输出到流中
    return os;
}

#include <iostream>

// 递归展开函数
template<typename T>
void printLastParam(std::ostream& os, const T& lastParam)
{
    os << lastParam;
}

template<typename T, typename... Args>
void printLastParam(std::ostream& os, const T& firstParam, const Args&... args)
{
    os << firstParam << ", ";
    printLastParam(os, args...);
}

// 重载 operator << 函数
template<typename... Args>
std::ostream& operator<<(std::ostream& os, const std::tuple<Args...>& tuple)
{
    os << "(";
    printLastParam(os, args...);
    os << ")";
    return os;
}

int main()
{
    std::tuple<int, double, std::string> myTuple(42, 3.14, "Hello");

    std::cout << myTuple << std::endl;

    return 0;
}