Difference between references and pointers [duplicate]

Question

Possible Duplicate:
What are the differences between pointer variable and reference variable in C++?

What does Class& mean in c++ and how is it different from Class*?

Class& foo;
Class* foo;

Answer 1

The & version represents a reference while the * version represents a pointer. The difference is far too big for a typical SO post. I suggest you start at the C++ FAQ lite

http://www.parashift.com/c++-faq-lite/references.html

I usually don't like to answer posts with a "you should use google" answer. However this is one topic that I highly advise you google. In particular google "c++ pointers vs. references". There is a wealth of information available on this topic and the discussions on those pages will trump anything we'll write here.

Answer 2

The * is a pointer, the & is a reference. The difference between the two is that a pointer is an area of memory that must be dereferenced, eg. by means of the -> operator in order to be "seen" as a class instance. A reference is instead an "alias", just an alternative name for the same class instance. You don't need to use the -> operator with a reference. You use the dot operator.

Personally, I rarely used the references, mostly when I had a value object that I allocated on the stack. The new operator always returns a pointer, which you then have to dereference. Moreover, one of the most problematic issues of the references is that you cannot set them to NULL. In some cases, it is handy to have a function that accepts either an object pointer or NULL. If your function accepts a reference, you cannot pass a NULL (you could use the Null object pattern, however)