使用类模板时的一点困惑

 1 #include<string>
 2 #include<iostream>
 3 
 4 using namespace std;
 5 
 6 ///通过嵌套实现元则
 7 template<typename T,typename N>
 8 class my_tuple
 9 {
10 public:
11     T value;
12     N next;
13     my_tuple(T const &v,N const &n):value(v),next(n){}
14 };
15 template<typename T,typename N>
16 my_tuple<T,N> push(T const &v,N const &n)
17 {
18     return my_tuple<T,N>(v,n);
19 }
20 int main()
21 {
22     typedef my_tuple<int ,char> tuple2;
23     typedef my_tuple<float,tuple2> tuple3;
24     typedef my_tuple<std::string,tuple3> tuple4;
25 
26     tuple4 tup4 = push(std::string("awesome"),
27　　　　　　　　　　　　　　　push(.5f,push(2,‘a‘)));
28     cout<<tup4.value<<","
29           <<tup4.next.value<",";
30     cout<<tup4.next.next.value<<","
31           <<tup4.next.next.next<<endl;
32      //此时输出结果为: awesome,0.52,a
33      //奇怪的是逗号少输出了一个
34      //开始我用的输出格式是cout<<tup4.value<<","<<tup4.next.value<","<<tup4.next.next.value<<","<<tup4.next.next.next<<endl;
35      //直接就报错了：test.cpp||error: invalid operands of types ‘const char [2]‘ and ‘int‘ to binary ‘operator<<‘
36 }