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Hiding an Assignment Operator

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Hiding an Assignment Operator

Nov 13th, 2008

For a lab, my instructor asked us to include an assignment operator with our class, but to hide it. Does this mean to declare it as private and just leave an empty implementation? Is this common/useful?

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Re: Hiding an Assignment Operator

Nov 13th, 2008

> declare it as private and just leave an empty implementation?
ideally, declare it as private and do not define it.

> Is this common/useful?
useful, yes. common, not all that much.
if there is a class that you write (for example a window), and want its instances not to have value semantics, you need to suppress any compiler-generated copy constructor and assignment operators.

 Help with Code Tags 
 c++ Syntax (Toggle Plain Text) 
struct window
{
    // ...
    private:
       window( const window& ) ; // do not define this
       void operator= ( const window& ) ; // do not define this
    // ...
}
struct window
{
    // ...
    private:
       window( const window& ) ; // do not define this
       void operator= ( const window& ) ; // do not define this
    // ...
}

see: http://www.boost.org/doc/libs/1_37_0...ss_noncopyable

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Join Date: Nov 2007

Posts: 390

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Re: Hiding an Assignment Operator

Nov 13th, 2008

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Originally Posted by vijayan121

> declare it as private and just leave an empty implementation?
ideally, declare it as private and do not define it.

> Is this common/useful?
useful, yes. common, not all that much.
if there is a class that you write (for example a window), and want its instances not to have value semantics, you need to suppress any compiler-generated copy constructor and assignment operators.
Help with Code Tags

c++ Syntax (Toggle Plain Text)
struct window
{
    // ...
    private:
       window( const window& ) ; // do not define this
       void operator= ( const window& ) ; // do not define this
    // ...
}
struct window { // ... private: window( const window& ) ; // do not define this void operator= ( const window& ) ; // do not define this // ... }
see: http://www.boost.org/doc/libs/1_37_0...ss_noncopyable