In my library-header I have some forward declaration of classes. I also have a forward-declaration of a template class like this: template <class T> class NDataObjectTx; class NETLIBC_EXPORT netLibC { template <typename T> bool getDataObject(NDataObjectTx<T> **dataObject); ...
template<typename T> class Tree { friend class Factory; // OK even if first declaration of Factory friend class MyNode<T>; // error MyNode未找到声明 }; template<typename T> class Stack { public: // assign stack of elements of type T2 template<typename T2> Stack<T>& operator= (...
#include <iostream> struct Configuration { static constexpr int foo = 12; }; // forward declaration of template class Big template <Configuration config> class Big; template <Configuration config> class Small { public: Small(Big<config>& big): big(big) { } void doit() ...
template<classT>classCMyMatrix{private:introw;intcol; T** elements;public:CMyMatrix(introw,intcol);voidSetMatrix(T* data,introw,intcol);// declares template friend;// note that all the instantiations of DisplayMatrix become friendtemplate<classX>friendvoidDisplayMatrix(CMyMatrix<X>...
class NdGreater { }; int main() { NdGreater n1, n2; ::max(n1, n2); // 不支持 > 编译报错 } 2.模板编译时会进行两阶段检查 a.模板定义时,进行和类型参数无关的检查,如未定义的符号等。 b.模板实例化时,进行类型参数相关的检查。
Instantiating a Class Template 为了实例化一个 class template，我们需要显式地提供类型信息，例如 Blob<int> ia; // Blob<int>Blob<int> ia2 = {0, 1, 2, 3, 4} 编译器会实例化以下代码 template <> class Blob<int> {typedef typename std::vector<int>::size_type size_type; Blob(); ...
// Forward-declare the template. template <class T> struct S; // Cause the specialization declaration to be instantiated. The // "instantiated from" declaration is set to the one above. typedef S<int> S_of_int; // Now define the template. ...
// error: 'template<class T, class> Test::Test(const T&)' cannot be overloaded with // 'template<class T, class> Test::Test(const T&)' template<typename T, typename = std::enable_if_t< std::is_convertible_v<std::decay_t<T>, Fabrikam::Point>>> ...
template<class T> class TestClass; // forward declaration template<class T> void someFunc(TestClass<T> const*); // func decl template<class T> class TestClass { friend void someFunc<T>(TestClass const*); // now it uses the func // declared above }; ... Victor Jul 22 '05 #2 ...
// forward declaration template<typename T> class List; template<typename T> ostream& op << ( ostream& ostr, const List<T>& lst); template<typename T> class List { public: List(int n = 0, T val); const T& operator[ ](int i) const; T& operator[ ](int i); int size() ...