Tóm Tắt
Case 1
this is a pointer to an object of a class, on which the non-static member function was called. Moreover, when used as an expression the value-category of this is prvalue.
When we call a non-static member function on an object of the class, the address of that object is implicitly passed as the first argument of that member function. This is possible because every non-static member function has an implicit parameter named this which is of type X* for a nonconst member function and const X* for a const member function, where X is some class.
Case 2
When we apply * on this the result is the object to which the pointer this was pointing. We are basically dereferencing the this pointer. That is, *this gives us the object to which the pointer this points. In other words, we get the object on which we called the non-static member function.
Moreover, when used as an expression the value category of *this is lvalue. Also, note that
The type of an expression is never a reference.
Note that lvalue expression is different from lvalue reference. The answer by Marcelo Cantos and comment by cigien seems to be confusion these two concepts.
Summary
this
*this
Pointer to an object of a class on which the non-static member function was called.
Result of dereferencing the this pointer. The result is the actual object on which the non-static member function was called.
prvalue-expression
lvalue-expression
