c++控制实例化没明白哪位给个简单的例子感激不尽。

……所以有什么好讲的

one.h
template<typename T> class one{
public:
one()=default;
one(const T& words):s(words){}
private:
T s;
};

#include"one.h"
#include<iostream>
using namespace std;
int main()
{
template class one<string>;
one<string> some("shihuawoaini");
return 0;
}

D:\C++11\Dev-Cpp\MinGW64\include\extern.cppIn function 'int main()':
62D:\C++11\Dev-Cpp\MinGW64\include\extern.cpp[Error] expected primary-expression before 'template'
62D:\C++11\Dev-Cpp\MinGW64\include\extern.cpp[Error] expected ';' before 'template'

An explicit instantiation shall appear in an enclosing namespace of its template. 这跟extern template有什么关系