编译: g++ tuple.cpp -std=c++14
c++14支持函数返回auto的返回类型，c++11需要返回类型后置。
由于 get<N>(tuple)中的N必须是常量，用普通的循环遍历不了，tuple的特性很多是在编译期
完成的。

#include <iostream>#include <tuple>using namespace std;template<typename T, size_t N>struct RTuple{ static auto reverse(T& tup) { return move( tuple_cat( make_tuple(get<N-1>(tup)), RTuple<T,N-1>::reverse(tup)) ); }};template<typename T >struct RTuple<T, 1>{ static auto reverse(T& tup) { return move( make_tuple(get<0>(tup)) ); }};template<typename T>struct RTuple<T,0>{ static auto reverse(T& tup) { return move(tup); }};int main(int argc, char* argv[]){ auto t1 = make_tuple(1,2,3,4); auto in1 = RTuple<decltype(t1),4>::reverse(t1); cout<<get<0>(t1)<<","; cout<<get<1>(t1)<<","; cout<<get<2>(t1)<<","; cout<<get<3>(t1)<<endl; cout<<get<0>(in1)<<","; cout<<get<1>(in1)<<","; cout<<get<2>(in1)<<","; cout<<get<3>(in1)<<endl; tuple<> t2; auto size = tuple_size<decltype(t2)>::value; cout<<size<<endl; //if ( size > 0 ) // cout<<get<0>(t2)<<endl; auto in2 = RTuple<decltype(t2),0>::reverse(t2); size = tuple_size<decltype(in2)>::value; cout<<size<<endl; //if ( size > 0 ) // cout<<get<0>(in2)<<endl; return 0;}