c++ tuple的操作

tuple(不定数值组)的操作
1.初始化 见Init()//class tuple<>构造函数是
explicit的,因此不支持隐式转换
2.其他tuple的特性 见special
3.tuple的输出 见output()等

#include<iostream>#include<tuple>using namespace std;void Init(){    //常规初始化    tuple<int, double, string> t1(3, 3.14, "Wh");//...    //用pair初始化tuple    pair<int, double> p(2, 3);    tuple<int, double> t2(p);    //other    int a = 3;    double b = 3.14;    //tie()更多见 tieIntuple()    tuple<int&, double&> p3 = tie(a, b);    auto p4 = make_tuple(ref(a), ref(b));}void tieIntuple(){    int a = 4;    double b = 4.2;    //tie返回的类型是tuple<int&,double&>    tuple<int, double> p1 = tie(a, b);    tuple<int&, double&> p2 = tie(a, b);    --a;    b = 5.3;    cout << get<0>(p1) << ends << get<1>(p1) << endl;    cout << get<0>(p2) << ends << get<1>(p2) << endl;    //通过tie()得到特定位置的值    double d = 0.0;    tie(ignore, d) = p2;    cout << d << endl;}void special(){    //得到类型个数    cout << tuple_size < tuple<int, double, double>>::value;    //得到指定位置类型    tuple_element<1, tuple<int, double, double>>::type d = 3.14;    cout << d << endl;    //将多个tuple串接成一个tuple    auto tp = tuple_cat(make_tuple(3.22, 3), tie(d));}template<int Index,int Max,typename ...Args>struct PRINT_TUPLE{    static void print(ostream& os, const tuple<Args...>& t)    {        os << get<Index>(t) << (Index + 1 == Max ? "" : ",");        PRINT_TUPLE<Index + 1, Max, Args...>::print(os, t);    }};template<int Max,typename ...Args>struct PRINT_TUPLE<Max, Max, Args...>{    //无实例调用必须声明为静态方法    static void print(ostream& os,const tuple<Args...>& t)    {    }};template<typename ...Args>ostream& operator <<(ostream& os, const tuple<Args...>& t){    os << "[";    PRINT_TUPLE<0, sizeof...(Args), Args...>::print(os, t);    return os << "]";}void output(){    tuple<int, double, double> t(3, 2.33, 3.22);    cout << t;}int main(){    //Init();    //tieIntuple();    //special();    output();    system("pause");    return 0;}