c++11 - operate on c++ 11 variadic template parameters, store into tuple -


i'm trying learn bit of c++ 11 variadic template arguments.

i want take list of floating point input arguments converttest(), return std::tuple of ints. try compile following in g++:

template<typename ...argsin, typename ...argsout> static inline std::tuple<argsout...> converttest(float nextarg, argsin... remainingargs) {     auto = converttest(remainingargs...);     auto b = std::make_tuple(int(nextarg));     auto c = std::tuple_cat(a, b);      return c; }  static inline std::tuple<int> converttest(float lastargin) {     return std::make_tuple((int)lastargin); }  int main() {     auto res = converttest(0.5f, 10.11f);     return 0; }

i following error:

 error: conversion 'std::tuple<int, int>' non-scalar type 'std::tuple<>' requested

i'm not sure why return type std::tuple<argsout...> resolve std::tuple<>. ideas?

i've tried making return type auto, complaints missing trailing return types in case.

any ideas?

argoutare non deducible, become empty list. have write function in order instead

template<typename ... argsout, typename ...argsin> static std::tuple<argsout...> converttest(float nextarg, argsin... remainingargs);

and call it

converttest<int, int>(0.5f, 10.11f);

btw, may write (removing fact take exclusively float)

template<typename ...args> auto converttest(args... args) -> decltype(std::make_tuple(static_cast<int>(args)...)) {     return std::make_tuple(static_cast<int>(args)...) }

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