std::numeric_limits<T>::radix
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                    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 (since C++20) | 2 | 
| char16_t (since C++11) | 2 | 
| char32_t (since C++11) | 2 | 
| short | 2 | 
| unsigned short | 2 | 
| int | 2 | 
| unsigned int | 2 | 
| long | 2 | 
| unsigned long | 2 | 
| long long (since C++11) | 2 | 
| unsigned long long (since C++11) | 2 | 
| float | FLT_RADIX | 
| double | FLT_RADIX | 
| long double | FLT_RADIX | 
See also
|    [static]  | 
  number of radix digits that can be represented without change (public static member constant)  | 
|    [static]  | 
  one more than the smallest negative power of the radix that is a valid normalized floating-point value  (public static member constant)  | 
|    [static]  | 
  one more than the largest integer power of the radix that is a valid finite floating-point value  (public static member constant)  |