std::numeric_limits<T>::is_signed - cppreference.com
From cppreference.com
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(until C++11) | |
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(since C++11) | |
The value of std::numeric_limits<T>::is_signed is true for all signed arithmetic types T and false for the unsigned types. This constant is meaningful for all specializations.
Standard specializations
T
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value of std::numeric_limits<T>::is_signed
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/* non-specialized */
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false
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bool
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false
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char
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implementation-defined |
signed char
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true
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unsigned char
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false
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wchar_t
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implementation-defined |
char8_t (since C++20)
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false
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char16_t (since C++11)
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false
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char32_t (since C++11)
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false
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short
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true
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unsigned short
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false
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int
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true
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unsigned int
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false
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long
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true
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unsigned long
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false
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long long (since C++11)
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true
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unsigned long long (since C++11)
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false
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float
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true
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double
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true
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long double
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true
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Example
#include <iostream> #include <iomanip> #include <limits> template<typename T> struct test { test(const char* name, int w = 15) { std::cout << std::left << std::setw(w) << (std::numeric_limits<T>::is_specialized ? name : "non-specialized") << " : " << (std::numeric_limits<T>::is_signed ? "" : "un") << "signed\n"; } }; int main() { test<bool>{"bool"}; test<char>{"char"}; test<wchar_t>{"wchar_t"}; test<char16_t>{"char16_t"}; test<char32_t>{"char32_t"}; test<float>{"float"}; struct delusion{}; test<delusion>{"delusion"}; test<decltype(42)>{"decltype(42)"}; }
Possible output:
bool : unsigned char : signed wchar_t : signed char16_t : unsigned char32_t : unsigned float : signed non-specialized : unsigned decltype(42) : signed
See also
| checks if a type is a signed arithmetic type (class template) [edit] | |
| identifies integer types (public static member constant) [edit] | |
| identifies exact types (public static member constant) [edit] | |
| identifies types that represent a finite set of values (public static member constant) [edit] |