17. The need for overloaded assignment operator

• How do we fix the problem with assignment?

• We must provide our own version of the assignment operator to prevent Rectangle from making shallow assignment:

  
      // C++ overloaded assignment operator:
      Rectangle& operator=( Rectangle const& another_rectangle_ )
      {
          if ( this == &another_rectangle_ ) {
              // avoid assignment to self:
              return *this;
          }
          width = another_rectangle_.width;
          height = another_rectangle_.height;
          set_name( another_rectangle_.ptr_name );
          return *this;
      }