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Re: "default constructor"

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From	Arne Vajhøj <arne@vajhoej.dk>
Newsgroups	comp.lang.java.programmer, comp.lang.c++
Subject	Re: "default constructor"
Date	Wed, 21 Jun 2017 12:52:41 -0400
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Cross-posted to 2 groups.

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On 6/18/2017 9:49 PM, Stefan Ram wrote:
>    A default constructor is a constructor that misses something.
> 
>    In C++, it is a constructor that can be called with missing
>    arguments (no arguments).
> 
>        C++ 12.1p4:
> 
>        A default constructor for a class X is a constructor of
>        class X for which each parameter that is not a function
>        parameter pack has a default argument (including the
>        case of a constructor with no parameters).
> 
>    In Java, it is a constructor that is generated when an
>    explicit constructor declaration is missing. The generated
>    constructor just so happens to have no parameters, but
>    an explicitly declared constructor with no parameters is
>    not a default constructor, but replaces it:
> 
>        JLS8 13.4.12
> 
>        Adding one or more constructor declarations to the
>        source code of such a class will prevent this default
>        constructor from being implicitly declared, effectively
>        deleting a constructor, unless one of the new
>        constructors also has no parameters, thus replacing the
>        default constructor.
> 
>    Summary (simplified): In C++, "default constructor" means
>    "any constructor that does not require an argument".
>    In Java, it means "the constructor that is generated if
>    the user does not declare any constructor".

So?

C++ and Java are two different languages.

They also have somewhat different associated terminologies.

No surprise.

Arne

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Re: "default constructor" Arne Vajhøj <arne@vajhoej.dk> - 2017-06-21 12:52 -0400

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