Can a template class be a friend?

Can a template class be a friend?

Many-to-one: All instantiations of a template function may be friends to a regular non-template class. One-to-one: A template function instantiated with one set of template arguments may be a friend to one template class instantiated with the same set of template arguments.

What is the syntax of friend function in C++?

Declaration of a friend function in C++ class class_name { friend data_type function_name(arguments/s); //syntax of friend function. }; In the above declaration, the keyword friend precedes the function. We can define the friend function anywhere in the program like a normal C++ function.

Can we declare a template class as the friend of another class?

Is not allowed because template parameters cannot shadow each other. Nested templates must have different template parameter names.

How do you declare a friend function in C++?

A friend function is declared inside the class with a friend keyword preceding as shown below. class className{ …… friend returnType functionName(arg list); }; As shown above, the friend function is declared inside the class whose private and protected data members are to be accessed.

Can constructor be a friend function?

1 Answer. 5) When a friend declaration refers to an overloaded name or operator, only the function specified by the parameter types becomes a friend. A member function of a class X can be a friend of a class Y.

Can a friend function be private?

The friend function can be a member of another class or a function that is outside the scope of the class. A friend function can be declared in the private or public part of a class without changing its meaning.

What are the advantages of friend function in C++?

Benefits of friend function

• A friend function is used to access the non-public members of a class.
• It allows to generate more efficient code.
• It provides additional functionality which is not normally used by the class.
• It allows to share private class information by a non member function.

What is the syntax of declaring friend class?

Only the class implementer can declare who its friends are. A function or class cannot declare itself as a friend of any class. In a class definition, use the friend keyword and the name of a non-member function or other class to grant it access to the private and protected members of your class.

Which rule will not affect the friend function?

1. Which rule will not affect the friend function? Explanation: Friend is used to access private and protected members of a class from outside the same class. 2.

Why do we use friend function?

They are used in situations where we want a certain class to have access to another class’s private and protected members. Classes declared as friends to any another class will have all the member functions become friend functions to the friend class. Friend functions are used to work as a link between the classes.

How is a template function related to a friend function?

One-to-one: A template function instantiated with one set of template arguments may be a friend to one template class instantiated with the same set of template arguments. This is also the relationship between a regular non-template class and a regular non-template friend function.

How is a friend function generated in C + +?

The third approach solves this problem by relying on C++’s template instantiation mechanism to generate a non-template friend function associated with each instantiation of a template class.

Where do I find the friend specifier in cppreference?

Both function template and class template declarations may appear with the friend specifier in any non-local class or class template (although only function templates may be defined within the class or class template that is granting friendship).

How to make a friend Declaration in cppreference?

Template friends. A template friend declaration can name a member of a class template A, which can be either a member function or a member type (the type must use elaborated-type-specifier ). Such declaration is only well-formed if the last component in its nested-name-specifier (the name to the left of the last ::) is a simple-template-id…