In C++, a member function of a class can be defined inside another member function of the same class. This is called nesting of member functions. Nesting of member functions is also known as local classes or inner classes.
The syntax for defining a nested member function is as follows:
In the above example, the member function
outerFunc contains a nested class
InnerClass, which in turn contains a nested member function
The nested member function
innerFunc can access the data members and other member functions of the enclosing class
MyClass directly. However, it cannot access the local variables or parameters of the enclosing member function
Nesting of member functions is useful in situations where a function is only needed within the scope of another function and does not need to be accessed by the rest of the class or other classes. It can also help to organize code and improve readability.
Note that nesting of member functions is not commonly used in C++, and can be replaced with other techniques such as lambda functions and function objects in most cases.