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(C++11)(until C++20)
(C++11)(deprecated in C++20)
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(C++11)(until C++20)(C++17)
static const int radix;
(until C++11)
static constexpr int radix;
(since C++11)

The value of std::numeric_limits<T>::radix is the base of the number system used in the representation of the type. It is 2 for all binary numeric types, but it may be, for example, 10 for IEEE 754 decimal floating-point types or for third-party binary-coded decimal integers. This constant is meaningful for all specializations.

Standard specializations

T value of std::numeric_limits<T>::radix
/* non-specialized */ 0
bool 2
char 2
signed char 2
unsigned char 2
wchar_t 2
char8_t 2
char16_t 2
char32_t 2
short 2
unsigned short 2
int 2
unsigned int 2
long 2
unsigned long 2
long long 2
unsigned long long 2
double FLT_RADIX
long double FLT_RADIX

See also

number of radix digits that can be represented without change
(public static member constant)
one more than the smallest negative power of the radix that is a valid normalized floating-point value
(public static member constant)
one more than the largest integer power of the radix that is a valid finite floating-point value
(public static member constant)