c++ - 如何将模板函数传递给另一个函数

Question

我有以下模板函数，现在我想添加一个函数 testfun，其参数将是每个模板函数及其参数。但我不知道如何定义和实现 testfun。任何意见表示赞赏。谢谢！

template<typename T>
T hoo(T x)
{
    return x;
}

template<typename T, typename... Args>
T hoo(T first, Args... rest)
{
    return first + hoo(rest...);
}

int a = 1, b = 2, c = 3;
int tsum = hoo<int>(a, b);
std::cout << tsum << std::endl;

std::string sa = "a", sb = "b";
std::string tssum = hoo<std::string>(sa, sb);
std::cout << tssum << std::endl;

testfun(hoo, a, b);        //testfun looks like this
testfun(hoo, sa, sb);      //testfun looks like this
//[Update] Add more request
testfun(hoo, a, b, c);     //testfun also support this

Answer 1

我假设你想要：

template <typename T, typename... Args>
T testfun(T (&f) (T, Args...), T tail, Args... queue)
{
    return f(tail, queue...); // or any other implementation
}