There is a simple conversion between pointers and references: the address-of operator ( &) will yield a pointer referring to the same object when applied to a reference, and a reference which is initialized from the dereference ( *) of a pointer value will refer to the same object as that pointer, where this is possible without invoking undefined behavior. Int & k // compiler will complain: error: `k' declared as reference but not initialized In particular, local and global variables must be initialized where they are defined, and references which are data members of class instances must be initialized in the initializer list of the class's constructor. Because it is impossible to reinitialize a reference, they must be initialized as soon as they are created.
Note that for this reason, containers of references are not allowed. References cannot be null, whereas pointers can every reference refers to some object, although it may or may not be valid.Once a reference is created, it cannot be later made to reference another object it cannot be reseated.It is not possible to refer directly to a reference object after it is defined any occurrence of its name refers directly to the object it references.To call them variable, however, is in fact a misnomer, as we will see.Ĭ++ references differ from pointers in several essential ways:
Identifiers which are of reference type are called reference variables. Types which are of kind "reference to " are sometimes called reference types. Const int& ref is a constant reference pointing to a piece of storage having value 65.
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