Classes

Copy constructors (new)

A copy constructor is a standard class constructor, but it’s only argument is a class object itself. It essentially creates a new object with the same properties.

Copy assignments (overwrite)

Copy assignments work the same as copy constructors, but they overwrite an existing object.

Rule of three / five / zero

The rule of three states that every class you create should have:

• A destructor (for de-allocating)
• A copy constructor (for duplicating to a new object)
• A copy assignment constructor (for duplicating to an existing object)

The rule of five states that every class you create should have:

• A destructor (for de-allocating)
• A copy constructor (for duplicating to a new object)
• A copy assignment constructor (for duplicating to an existing object)
• A move constructor (for moving to a new object)
• A move assignment constructor (for moving to an existing object)

The rule of zero states that every class you create should have:

None of these, because you can use memory safe datatypes like STD vectors, strings, unique_ptr’s, etc. This way, memory allocation happens automatically.

Access

Access modifiers decide if other parts of your code have access to variables and functions in a class.

C++ has private, public, and protected just [[School/Year 1/P2/Software-development/Object Oriented Programming#Encapsulation|like C#]], but c++ also has something else: a friend modifier.
Friend tells the program that exceptions for certain classes are made, which give them access to private/protected methods and variables.