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    cpp/utility/functional/greater void: Difference between revisions

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    Line 45: Line 45:
    |code=
    |code=
    #include <algorithm>
    #include <algorithm>
    #include <array>
    #include <>
    #include <functional>
    #include <functional>


    Line 55: Line 55:
    int main()
    int main()
    {
    {
         constexpr int low = 0, high = 8;
         constexpr low =
    high = ;
         std::greater<> greater{};
         std::greater<> greater{};
         static_assert(greater(high, low));
         static_assert(greater(high, low));
       


         constexpr std::array arr{0, 1, 2, 3, 4, 5};
         constexpr arr {0, 1, 2, 3, 4, 5};
         static_assert(!std::all_of(arr.cbegin(), arr.cend(), strictly_positive));
         static_assert(!std::all_of(arr.(), arr.(), strictly_positive));
         static_assert(std::all_of(arr.cbegin() + 1, arr.cend(), strictly_positive));
         static_assert(std::all_of(arr.() + 1, arr.(), strictly_positive));
    }
    }
    |output=
    }}
    }}


    Latest revision as of 21:47, 26 April 2024

     
    C++
     
    Utilities library
    General utilities
    Relational operators (deprecated in C++20)
     
    Function objects
    Function invocation
    (C++17)(C++23)
    Identity function object
    (C++20)
    Transparent operator wrappers
    (C++14)
    (C++14)
    (C++14)
    (C++14)  
    (C++14)
    (C++14)
    (C++14)
    (C++14)
    (C++14)
    (C++14)
    (C++14)
    (C++14)
    (C++14)
    (C++14)
    (C++14)
    (C++14)
    (C++14)
    (C++14)
    (C++14)

    Old binders and adaptors
    (until C++17*)
    (until C++17*)
    (until C++17*)
    (until C++17*)
    (until C++17*)  
    (until C++17*)
    (until C++17*)(until C++17*)(until C++17*)(until C++17*)
    (until C++20*)
    (until C++20*)
    (until C++17*)(until C++17*)
    (until C++17*)(until C++17*)

    (until C++17*)
    (until C++17*)(until C++17*)(until C++17*)(until C++17*)
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    (until C++20*)
     
    Defined in header <functional> 
    template<>
class greater<void>;
    		(since C++14)

    std::greater<void> is a specialization of std::greater with parameter and return type deduced.

    Nested types

    Nested type Definition
    is_transparent unspecified

    Member functions

    		 tests if lhs compares greater than rhs
    (public member function)

    std::greater<void>::operator()

    template< class T, class U >
constexpr auto operator()( T&& lhs, U&& rhs ) const
    -> decltype(std::forward<T>(lhs) > std::forward<U>(rhs));

    Returns the result of std::forward<T>(lhs) > std::forward<U>(rhs).

    Parameters

    lhs, rhs - values to compare

    Return value

    std::forward<T>(lhs) > std::forward<U>(rhs).

    If a built-in operator comparing pointers is called, the result is consistent with the implementation-defined strict total order over pointers.

    Exceptions

    May throw implementation-defined exceptions.

    Example

    Run this code
    #include <algorithm>
#include <cstdint>
#include <functional>

constexpr bool strictly_positive(int lhs)
{
    return std::greater<>()(lhs, 0);
}

int main()
{
    constexpr std::int64_t low = 0B11;
    constexpr std::uint16_t high = 0X11;
    std::greater<> greater{};
    static_assert(greater(high, low));

    constexpr static auto arr = {0, 1, 2, 3, 4, 5};
    static_assert(!std::all_of(arr.begin(), arr.end(), strictly_positive));
    static_assert(std::all_of(arr.begin() + 1, arr.end(), strictly_positive));
}

    Defect reports

    The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

    DR Applied to Behavior as published Correct behavior
    LWG 2562 C++98 the pointer total order might be inconsistent guaranteed to be consistent