std::numeric_limits::max_exponent(3)

NAME
std::numeric_limits::max_exponent - std::numeric_limits::max_exponent

Synopsis
   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 \(\scriptsize r^{n-1}\)rn-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 (C++20) 0
   char16_t (C++11) 0
   char32_t (C++11) 0
   short 0
   unsigned short 0
   int 0
   unsigned int 0
   long 0
   unsigned long 0
   long long (C++11) 0
   unsigned long long (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: // Run this code
 #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
               << "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
   min_exponent10 the smallest negative power of ten that is a valid normalized
   [static] floating-point value
                  (public static member constant)
   min_exponent one more than the smallest negative power of the radix that is a
   [static] valid normalized floating-point value
                  (public static member constant)
   max_exponent10 the largest integer power of 10 that is a valid finite floating-point
   [static] value
                  (public static member constant)