11: References & the Copy-Constructor

References are like constant pointers that are automatically dereferenced by the compiler.

Although references also exist in Pascal, the C++ version was taken from the Algol language. They are essential in C++ to support the syntax of operator overloading (see Chapter 12), but they are also a general convenience to control the way arguments are passed into and out of functions.

This chapter will first look briefly at the differences between pointers in C and C++, then introduce references. But the bulk of the chapter will delve into a rather confusing issue for the new C++ programmer: the copy-constructor, a special constructor (requiring references) that makes a new object from an existing object of the same type. The copy-constructor is used by the compiler to pass and return objects by value into and out of functions.

Finally, the somewhat obscure C++ pointer-to-member feature is illuminated.