问题描述
在 C 中确定数据类型(即 int、char.etc)的最小值和最大值的函数是什么?
What is the function to determine the min and max possible of value of datatypes (i.e, int, char.etc) in C?
推荐答案
你会想要使用 limits.h 提供以下常量(根据链接的参考):
You'll want to use limits.h which provides the following constants (as per the linked reference):
SCHAR_MIN : minimum value for a signed char
SCHAR_MAX : maximum value for a signed char
UCHAR_MAX : maximum value for an unsigned char
CHAR_MIN : minimum value for a char
CHAR_MAX : maximum value for a char
SHRT_MIN : minimum value for a short
SHRT_MAX : maximum value for a short
USHRT_MAX : maximum value for an unsigned short
INT_MIN : minimum value for an int
INT_MAX : maximum value for an int
UINT_MAX : maximum value for an unsigned int
LONG_MIN : minimum value for a long
LONG_MAX : maximum value for a long
ULONG_MAX : maximum value for an unsigned long
LLONG_MIN : minimum value for a long long
LLONG_MAX : maximum value for a long long
ULLONG_MAX : maximum value for an unsigned long long
PTRDIFF_MIN : minimum value of ptrdiff_t
PTRDIFF_MAX : maximum value of ptrdiff_t
SIZE_MAX : maximum value of size_t
SIG_ATOMIC_MIN : minimum value of sig_atomic_t
SIG_ATOMIC_MAX : maximum value of sig_atomic_t
WINT_MIN : minimum value of wint_t
WINT_MAX : maximum value of wint_t
WCHAR_MIN : minimum value of wchar_t
WCHAR_MAX : maximum value of wchar_t
CHAR_BIT : number of bits in a char
MB_LEN_MAX : maximum length of a multibyte character in bytes
其中 U*_MIN 由于显而易见的原因被省略(任何无符号类型的最小值为 0).
Where U*_MIN is omitted for obvious reasons (any unsigned type has a minimum value of 0).
同样float.h 提供限制对于 float 和 double 类型:
FLT_MIN : smallest normalised positive value of a float
FLT_MAX : largest positive finite value of a float
DBL_MIN : smallest normalised positive value of a double
DBL_MAX : largest positive finite value of a double
LDBL_MIN : smallest normalised positive value of a long double
LDBL_MAX : largest positive finite value of a long double
FLT_DIG : the number of decimal digits guaranteed to be preserved converting from text to float and back to text
DBL_DIG : the number of decimal digits guaranteed to be preserved converting from text to double and back to text
LDBL_DIG : the number of decimal digits guaranteed to be preserved converting from text to long double and back to text
浮点类型围绕零对称，因此最负有限数是最正有限数的否定 - 例如 float 范围从 -FLT_MAX 到 FLT_MAX.
Floating point types are symmetrical around zero, so the most negative finite number is the negation of the most positive finite number - eg float ranges from -FLT_MAX to FLT_MAX.
请注意，浮点类型只能精确表示其范围内的少量有限数量的值.随着存储的绝对值变大，可以精确表示的相邻数字之间的间距也变大.
Do note that floating point types can only exactly represent a small, finite number of values within their range. As the absolute values stored get larger, the spacing between adjacent numbers that can be exactly represented also gets larger.
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