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    std::conditional

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    C++
     
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    Grundtypen
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    Basic types
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    Grundtypen
    Feste Breite Integer-Typen(C++11)
    Numerische Grenzen
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    C numerische begrenzt Schnittstelle
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    is_const(C++11)
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    has_virtual_destructor(C++11)
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    is_same(C++11)
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    aligned_storage(C++11)
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    conditional(C++11)
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    integral_constant(C++11)
     
    definiert in Header <type_traits>
    template<bool B, class T, class F >
    struct conditional;
    		(seit C++11)
    Bietet Mitglied typedef type, die als T definiert wird, wenn B ist true Zeitpunkt der Kompilierung, oder als F wenn B ist false .
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    Provides member typedef type, which is defined as T if B is true at compile time, or as F if B is false.
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    Inhaltsverzeichnis

    [Bearbeiten]Mitglied Typen

    Mitglied Typ
    Original:
    Member type
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    		 Definition
    typeT if B ==true, F if B ==false

    [Bearbeiten]Mögliche Implementierung

    template<bool B, class T, class F>struct conditional {typedef T type;};   template<class T, class F>struct conditional<false, T, F>{typedef F type;};

    [Bearbeiten]Beispiel

    #include <iostream>#include <type_traits>#include <typeinfo>   int main(){typedef std::conditional<true, int, double>::type Type1;typedef std::conditional<false, int, double>::type Type2;typedef std::conditional<sizeof(int)>= sizeof(double), int, double>::type Type3;   std::cout<<typeid(Type1).name()<<'\n';std::cout<<typeid(Type2).name()<<'\n';std::cout<<typeid(Type3).name()<<'\n';}

    Output: 

    i d d

    [Bearbeiten]Siehe auch

    (C++11)
    verbirgt sich eine Funktion Überlast oder Vorlage Spezialisierung auf compile-time boolean basiert
    Original:
    hides a function overload or template specialization based on compile-time boolean
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    (Klassen-Template)[edit]
    Von „https://de.cppreference.com/mwiki/index.php?title=cpp/types/conditional&oldid=30141“
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