我想将类指针和仿函数作为类模板参数传递。我也不希望该类指针成为仿函数的本地成员。我想使用代码中其他地方使用的现有模板类，所以我想对这两个参数应用默认值，这样我就不必更改现有代码。
我的意图在这堂课中得到了解释。
class MyClass
{
int local;
/*Dont have member pointer in my current template*/
AnotherClass* anClass;
MyClass(AnotherClass* ptr)
{
/*dont want to create a brand new pointer in my template
the local pointer must be assigned a reference to a pre-existing pointer
passed as argument*/
anClass = ptr;
}
void DoSomething(int val )
{
local = InvokeLogic(val);
/*Dont have this function call DoSomeMore() in my template.
So I want another DoSomeMore() template argument which
is a function-object/functor */
anClass->DoSomeMore(local);
}
}
然而，实际上，我有这个模板目前缺少一些我想要的信息。
template <typename T>
class MyClass
{
T local;
/* AnotherClass* anClass; does not exist */
void DoSomething(T t)
{
local = InvokeLogic(t);
/* want to call this anClass->DoSomeMore(local);
but dont know how to call it. The DoSomething() function object can accept AnotherClass* anClass as a function argument.
*/
}
};
当 MyClass 的实例被创建时，AnotherClass* anClass 就存在了。