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 }
希望大神们看到了能给出一点提示
