std::numeric_limits::min_exponent

From cppreference.com


static const int min_exponent		(until C++11)

static constexpr int min_exponent		(since C++11)

The value of std::numeric_limits<T>::min_exponent10 is the lowest negative number n such that $r n-1$ , where r is std::numeric_limits<T>::radix is a valid normalized value of the floating-point type T.

[edit] Standard specializations


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

/* 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_MIN_EXP

double	DBL_MIN_EXP

long double	LDBL_MIN_EXP

[edit] Example

Demonstrates the relationships of min_exponent, min_exponent10, min, and radix for the type float:

#include <iostream>
int main()
{
    std::cout << "min() = " << std::numeric_limits<float>::min() << '\n'
              << "min_exponent10 = " << std::numeric_limits<float>::min_exponent10 << '\n'
              << std::hexfloat
              << "min() = " << std::numeric_limits<float>::min() << '\n'
              << "min_exponent = " << std::numeric_limits<float>::min_exponent << '\n';
}

Output:

min() = 1.17549e-38
min_exponent10 = -37
min() = 0x1p-126
min_exponent = -125

[edit] See also


radix [static]	the radix or integer base used by the representation of the given type (public static member constant)

min_exponent10 [static]	the smallest negative power of ten that is a valid normalized floating-point value (public static member constant)

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

max_exponent10 [static]	the largest integer power of 10 that is a valid finite floating-point value (public static member constant)

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