std::unsigned_integral

 

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核心語言概念 same_as (C++20) derived_from (C++20) convertible_to (C++20) common_reference_with (C++20) common_with (C++20) integral (C++20) signed_integral (C++20) unsigned_integral (C++20) floating_point (C++20) swappableswappable_with (C++20)(C++20) destructible (C++20) constructible_from (C++20) default_initializable (C++20)   move_constructible (C++20) copy_constructible (C++20) assignable_from (C++20)

比較概念 equality_comparableequality_comparable_with (C++20)(C++20) totally_orderedtotally_ordered_with (C++20)(C++20) 物件概念 movable (C++20) copyable (C++20) semiregular (C++20) regular (C++20) 可呼叫概念 invocableregular_invocable (C++20)(C++20) predicate (C++20) relation (C++20) equivalence_relation (C++20) strict_weak_order (C++20)

僅用於闡釋的概念 boolean-testable  (C++20)

 

定義於標頭檔案 <concepts>
template< class T > concept unsigned_integral = std::integral<T> && !std::signed_integral<T>;		(C++20 起)

概念 unsigned_integral<T> 滿足當且僅當 T 是整數型別且 std::is_signed_v<T> 為 false。

注意

unsigned_integral<T> 可能由非 無符號整數型別 的型別滿足，例如 bool。

示例

執行此程式碼

#include <concepts>
#include <iostream>
#include <string_view>
 
void test(std::signed_integral auto x, std::string_view text = "")
{
    std::cout << text << " (" + (text == "") << x << ") is a signed integral\n";
}
 
void test(std::unsigned_integral auto x, std::string_view text = "")
{
    std::cout << text << " (" + (text == "") << x << ") is an unsigned integral\n";
}
 
void test(auto x, std::string_view text = "")
{
    std::cout << text << " (" + (text == "") << x << ") is non-integral\n";
}
 
int main()
{
    test(42);               // signed
    test(0xFULL, "0xFULL"); // unsigned
    test('A');              // platform-dependent
    test(true, "true");     // unsigned
    test(4e-2, "4e-2");     // non-integral (hex-float)
    test("∫∫");             // non-integral
}

可能的輸出

(42) is a signed integral
0xFULL (15) is an unsigned integral
(A) is a signed integral
true (1) is an unsigned integral
4e-2 (0.04) is non-integral
(∫∫) is non-integral

參考文獻

• C++23 標準 (ISO/IEC 14882:2024)

• 18.4.7 算術概念 [concepts.arithmetic]

• C++20 標準 (ISO/IEC 14882:2020)

• 18.4.7 算術概念 [concepts.arithmetic]

另請參閱

is_integral (C++11)	檢查型別是否為整型 (類模板)
is_signed (C++11)	檢查型別是否為有符號算術型別 (類模板)