variadic-templates

I want to write a function magic_get , which can extract a value from a parameter pack by index, for example: int n = 0; n = magic_get<0>(1, 3, 5, 7); assert(1 == n); n = magic_get<1>(1, 3, 5, 7); assert(3 == n); n = magic_get<2>(1, 3, 5, 7); assert(5 == n); n = magic_get<3>(1, 3, 5, 7); assert(7 == n); How to implement magic_get ? template <size_t N, typename... Args> decltype(auto) magic_get(Args&&... as) noexcept { return std::get<N>(std::forward_as_tuple(std::forward<Args>(as)...)); } Change decltype(auto) to auto and add a trailing return type of decltype(/* the whole returned expression

I had nested partially specialized template code working with VS 2015 until I discovered that it was not standards-compliant . I want it to be so I twisted my code to overcome the former issue and also that one and have now hit a hard wall. Using variadic templates and partial specialization I would like to fill an array at compile-time given a fixed set of parameters. What I want to achieve also seems similar to this answer but I did not manage to make it work. Consider the following program: #include <cstdlib> template <typename T, std::size_t Size> struct Array; template <typename T, std:

I have a diamond inheritance scheme, where the last child should be able to inherit from many different parents. A /|\ / | \ B C ... | | | * * D E Now imagine I have a class D : public B , class E : public B, public C , etc. From D I want to call the same function of all its parents, which I am guaranteed exists due to the inheritance. My thought was that I could wrap this in some variadic template. Currently I have this: template <typename T> class A { public: A(T t) : mT(t) {} virtual ~A() {} virtual void doThings() = 0; protected: T mT; }; template <typename T, typename A = A<T>> class B :

i'm trying to achieve something like this: I have a templated base class which i want to inherit dynamically template<typename A, typename B> class fooBase { public: fooBase(){}; ~fooBase(){}; }; desired method: (something like this, not really sure how to do it) template <typename... Interfaces> class foo : public Interfaces... { public: foo(); ~foo(); } and my goal is to have the foo class act like this: second method: class foo() : public fooBase<uint8_t, float> , public fooBase<uint16_t, bool> , public fooBase<uint32_t, int> // and the list could go on { foo(); ~foo(); } with the second

What is the best way of implementing index-based insertion and deletion of a type in a variadic template type list (parameter pack)? Desired code/behavior: template<typename...> struct List { /* ... */ }; static_assert(is_same < List<int, char, float>::Insert<int, 0>, List<int, int, char, float> >()); static_assert(is_same < List<int, char, float>::Insert<int, 2>, List<int, char, int, float> >()); static_assert(is_same < List<int, char, float>::Remove<0>, List<char, float> >()); static_assert(is_same < List<int, char, float>::Remove<1>, List<int, float> >()); I tried an implementation based on

I was reading about variadic templates and I came across this example. The book mentions that to end the recursion process, the function print() is used. I really can't understand its use. Why does the author use this empty print() function? void print () // can't get why this function is used { } template <typename T, typename... Types> void print (const T& firstArg, const Types&... args) { std::cout << firstArg << std::endl; // print first argument print(args...); // call print() for remaining arguments } A variadic expression can capture 0 arguments or more . Take for example the call print