Re: A question about "this" pointer

From:

Victor Bazarov <v.Abazarov@comAcast.net>

Newsgroups:

comp.lang.c++

Date:

Tue, 20 Jan 2009 10:03:28 -0500

Message-ID:

<gl4p40$6n1$2@news.datemas.de>

Kai-Uwe Bux wrote:

Vols wrote:

"this" pointer points to the object for which the member function is
called. My question is :
When we must use a "this" pointer? any examples? thanks

1) In the last line of the assignment operator:

  A & operator= ( A const & other ) {
    ...
    return ( *this );
  }

More generally, whenever you want to return a reference to the current
object.

....or need the expression to yield the value "pointer to self", like
when passing it to some other funciton:

    void foo(A* pA);

    ...
    void A::bar() { // a non-static member function
        foo(this); // call another function with "my address"
    }

2) Sometimes this->some_member provides a convenient name to help name
resolution, e.g.:

  struct A {

    int a ( void ) const {
      return ( 3 );
    }

  };

  template < typename Base >
  struct B : public Base {

    int b ( void ) const {
      return ( this->a() );
    }

  };

  int main ( void ) {
    B<A> b_obj;;
    b_obj.b();
  }

V
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