std::numeric_limits<T>:: max_exponent

From cppreference.com
Utilities library
General utilities
Relational operators (deprecated in C++20)
static const int max_exponent ;
(until C++11)
static constexpr int max_exponent ;
(since C++11)

The value of std:: numeric_limits < T > :: max_exponent is the largest positive number n such that r n-1 , where r is std:: numeric_limits < T > :: radix , is a representable finite value of the floating-point type T .

Standard specializations

T value of std:: numeric_limits < T > :: max_exponent
/* non-specialized */ 0
bool 0
char 0
signed char 0
unsigned char 0
wchar_t 0
char8_t (since C++20) 0
char16_t (since C++11) 0
char32_t (since C++11) 0
short 0
unsigned short 0
int 0
unsigned int 0
long 0
unsigned long 0
long long (since C++11) 0
unsigned long long (since C++11) 0
float FLT_MAX_EXP
double DBL_MAX_EXP
long double LDBL_MAX_EXP

Example

Demonstrates the relationships of max_exponent , max_exponent10 , and max() for the type float :

#include <iostream>
#include <limits>
 
int main()
{
    std::cout << "max() = " << std::numeric_limits<float>::max() << '\n'
              << "max_exponent10 = " << std::numeric_limits<float>::max_exponent10 << '\n'
              << std::hexfloat << '\n'
              << "max() = " << std::numeric_limits<float>::max() << '\n'
              << "max_exponent = " << std::numeric_limits<float>::max_exponent << '\n';
}

Output:

max() = 3.40282e+38
max_exponent10 = 38
 
max() = 0x1.fffffep+127
max_exponent = 128

See also

the smallest negative power of ten that is a valid normalized floating-point value
(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)
the largest integer power of 10 that is a valid finite floating-point value
(public static member constant)