Pointers in C++ are almost identical to pointers in C, which is good. Otherwise, a lot of C code wouldn’t compile properly under C++. The only compile-time errors you will produce occur with dangerous assignments. If these are in fact what are intended, the compile-time errors can be removed with a simple (and explicit!) cast.

C++ also adds the reference from Algol and Pascal, which is like a constant pointer that is automatically dereferenced by the compiler. A reference holds an address, but you treat it like an object. References are essential for clean syntax with operator overloading (the subject of the next chapter), but they also add syntactic convenience for passing and returning objects for ordinary functions.

The copy-constructor takes a reference to an existing object of the same type as its argument, and it is used to create a new object from an existing one. The compiler automatically calls the copy-constructor when you pass or return an object by value. Although the compiler will automatically create a copy-constructor for you, if you think one will be needed for your class, you should always define it yourself to ensure that the proper behavior occurs. If you don’t want the object passed or returned by value, you should create a private copy-constructor.

Pointers-to-members have the same functionality as ordinary pointers: You can choose a particular region of storage (data or function) at runtime. Pointers-to-members just happen to work with class members instead of with global data or functions. You get the programming flexibility that allows you to change behavior at runtime.