Why is the "this" pointer in c++ a pointer and not a reference?

Answer 1

From Bjarne Stroustrup's C++ Style and Technique FAQ:

Why is "this" not a reference?

Because "this" was introduced into C++ (really into C with Classes) before references were added. Also, I chose "this" to follow Simula usage, rather than the (later) Smalltalk use of "self".