Request and Suppress Methods

Special methods #

Since C++11, there has been a list of special methods that the compiler can generate implicitly if we have not defined them:

• Default constructors and destructors.

• Copy/move constructors and copy/move assignment operators.

• new and delete operators for objects and C arrays of objects.

• The default and delete keywords can be used to guide the creation or suppression of these special methods.

• default can only be assigned to special methods that do not have any default arguments. Hence, it wouldn’t work with something like an ordinary class method or a parameterized constructor.

Let’s suppose we have a parameterized constructor for our Account class but no default constructor. The compiler can easily generate it for us. All we need to do is assign default to the default constructor.

...
Account() = default;
Account (double balance){this->balance = balance;}
...

The behavior of the compiler varies based on what special members the user has defined. We can find details in the diagram by Howard Hinnant below: