std::signed_integral (自 C++20 起)
来自 cppreference.com
定义在头文件 <concepts> 中 |
||
template< class T > concept signed_integral = std::integral<T> && std::is_signed_v<T>; |
(自 C++20 起) | |
仅当 T
是一个整型且 std::is_signed_v<T> 为 true 时,概念 signed_integral<T>
才满足。
内容 |
[编辑] 注释
signed_integral<T>
可能被一个不是 带符号整数类型 的类型满足,例如,char(在一个 char 是带符号的系统上)。
[编辑] 示例
运行此代码
#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 }
可能的输出
(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
[编辑] 参考
- C++23 标准 (ISO/IEC 14882:2024)
- 18.4.7 算术概念 [concepts.arithmetic]
- C++20 标准 (ISO/IEC 14882:2020)
- 18.4.7 算术概念 [concepts.arithmetic]
[编辑] 另请参阅
(C++11) |
检查一个类型是否为整型 (类模板) |
(C++11) |
检查一个类型是否为带符号算术类型 (类模板) |