std::numeric_limits::is_modulo
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< cpp | types | numeric limits
static const bool is_modulo |
(until C++11) | |
static constexpr bool is_modulo |
(since C++11) | |
The value of std::numeric_limits<T>::is_modulo is true for all arithmetic types T that handle overflows with modulo arithmetic, that is, if the result of addition, subtraction, multiplication, or division of this type would fall outside the range [min(), max()], the value returned by such operation differs from the expected value by a multiple of max()-min()+1.
[edit] Standard specializations
T | value of std::numeric_limits<T>::is_modulo |
/* non-specialized */ | false |
bool | false |
char | true |
signed char | true |
unsigned char | true |
wchar_t | true |
char16_t | true |
char32_t | true |
short | true |
unsigned short | true |
int | true |
unsigned int | true |
long | true |
unsigned long | true |
long long | true |
unsigned long long | true |
float | false |
double | false |
long double | false |
[edit] Example
Demonstrates the behavior of modulo types
#include <iostream> #include <type_traits> #include <limits> template<class T> typename std::enable_if<std::numeric_limits<T>::is_modulo>::type check_overflow() { std::cout << "\nmax value is " << std::numeric_limits<T>::max() << '\n' << "min value is " << std::numeric_limits<T>::min() << '\n' << "max value + 1 is " << std::numeric_limits<T>::max()+1 << '\n'; } int main() { check_overflow<int>(); check_overflow<unsigned long>(); // check_overflow<float>(); // compile-time error, not a modulo type }
Output:
max value is 2147483647 min value is -2147483648 max value + 1 is -2147483648 max value is 18446744073709551615 min value is 0 max value + 1 is 0
[edit] See also
[static] |
identifies integer types (public static member constant) |
[static] |
identifies the IEC 559/IEEE 754 floating-point types (public static member constant) |
[static] |
identifies exact types (public static member constant) |