myList.copyEven(myVector, yourList);

The statement above is a call to the function copyEven, a member function of the class AnyList, where:

myList is an object of the class AnyList

myVector is a vector of integers

yourList is an object of the class AnyList

function copy copies all the even elements stored in the vector into the calling object, and then copies all of the elements stored in the calling object into the AnyList parameter object.

It is irrelevant whether any of the object have elements or not.

Example:

Calling object is empty.

Vector parameter is: 1 2 3 4

AnyList object parameter is empty.

Function runs...

Calling object is: 2 4

Vector parameter is: 1 2 3 4

AnyList object parameter is: 2 4