std::numeric_limits<T>::min_exponent10

 

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numeric_limits
C 数值极限接口
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is_move_constructibleis_trivially_move_constructibleis_nothrow_move_constructible (C++11)(C++11)(C++11)
is_assignableis_trivially_assignableis_nothrow_assignable (C++11)(C++11)(C++11)
is_copy_assignableis_trivially_copy_assignableis_nothrow_copy_assignable (C++11)(C++11)(C++11)
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std::numeric_limits

静态常量

numeric_limits::is_specialized

numeric_limits::is_signed

numeric_limits::is_integer

numeric_limits::is_exact

numeric_limits::has_infinity

numeric_limits::has_quiet_NaN

numeric_limits::has_signaling_NaN

numeric_limits::has_denorm

numeric_limits::has_denorm_loss

numeric_limits::round_style

numeric_limits::is_iec559

numeric_limits::is_bounded

numeric_limits::is_modulo

numeric_limits::digits

numeric_limits::digits10

numeric_limits::max_digits10 (C++11)

numeric_limits::radix

numeric_limits::min_exponent

numeric_limits::min_exponent10

numeric_limits::max_exponent

numeric_limits::max_exponent10

numeric_limits::traps

numeric_limits::tinyness_before

静态成员函数

numeric_limits::min

numeric_limits::lowest (C++11)

numeric_limits::max

numeric_limits::epsilon

numeric_limits::round_error

numeric_limits::infinity

numeric_limits::quiet_NaN

numeric_limits::signaling_NaN

numeric_limits::denorm_min

辅助类型

float_round_style

float_denorm_style

 

static const int min_exponent10;		(C++11 前)
static constexpr int min_exponent10;		(C++11 起)

std::numeric_limits<T>::min_exponent10 的值是满足 \(\scriptsize 10^n\)10n
是浮点类型 T 的合法正规值的最低负数 n 。

标准特化

T	std::numeric_limits<T>::min_exponent10 的值
/* 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_MIN_10_EXP
double	DBL_MIN_10_EXP
long double	LDBL_MIN_10_EXP

示例

为 float 类型演示 min_exponent、 min_exponent10、 min 及 radix 的关系：

运行此代码

#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';
}

输出：

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

参阅

min_exponent [静态]	底的该数次幂是合法正规浮点值的最小负数加一 (公开静态成员常量)
max_exponent [静态]	底的该数次幂是合法有限浮点值的最大整数加一 (公开静态成员常量)
max_exponent10 [静态]	10 的该数次幂是合法有限浮点值的最大整数 (公开静态成员常量)