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What does this construct A <B> :: c ("d") mean? Space name with pattern?

It appears to be ca function that takes "d" as an argument. I know what is ::used for the specified namespaces and their namespaces. But what does it mean A<B>? I know what Ba class is. I also know that templates can be used for classes, functions, and structures. But in this example, it looks like we are using a template for a namespace.

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2 answers

This means that you have a class template Athat takes a type parameter, and you create this template with the type Bas its type argument.

, , (1) c ( ), , (2) c , ( ).

, A, (::), , ( , , ).

(1) ( ):

#include <iostream>

struct B { };

template<typename T>
struct A
{
    static void c(const char* s) { std::cout << s; }
};

int main()
{
    A<B>::c("d");
}

(1) , ( ):

#include <iostream>

struct B { void operator () (const char* c) { std::cout << c;  } };

template<typename T> 
struct A
{
    static T c;
};

template<typename T>
T A<T>::c;

int main()
{
    A<B>::c("d");
}

(2) ( ):

#include <iostream>

struct B { B(const char* s) { std::cout << s; } };

template<typename T> 
struct A
{
    typedef T c;
};

int main()
{
    A<B>::c("d");
}
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:: , .

c() A<B>. .

, c (, , operator()(const char *))), const char * class struct, A<B>, const char *.

( , .)

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