std::numeric_limits::max_exponent10

From Cppreference


static const int max_exponent10		(pre-C++11 version)

static constexpr int max_exponent10		(C++11 version)

The value of std::numeric_limits<T>::max_exponent10 is the largest positive number n such that $10 n$ is a representable finite value of the floating-point type T.

[edit] Standard specializations


`T`	value of std::numeric_limits<T>::max_exponent10

/* non-specialized */	0

bool	0

char	0

signed char	0

unsigned char	0

wchar_t	0

char16_t	0

char32_t	0

short	0

unsigned short	0

int	0

unsigned int	0

long	0

unsigned long	0

long long	0

unsigned long long	0

float	FLT_MAX_10_EXP

double	DBL_MAX_10_EXP

long double	LDBL_MAX_10_EXP

[edit] Example

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

#include <iostream>
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

[edit] See also

min_exponent10

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

max_exponent

one more than the largest integer power of the radix that is a valid finite floating-point value
(public static member constant)

max_exponent10

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