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📅  最后修改于: 2020-12-19 05:37:39             🧑  作者: Mango

limits.h标头确定各种变量类型的各种属性。此标头中定义的宏限制了各种变量类型(例如char，int和long)的值。

这些限制指定变量不能存储超出这些限制的任何值，例如，无符号字符最多可以存储255。

图书馆巨集

以下值为特定于实现的值，并使用#define指令定义，但这些值不得低于此处给出的值。

Macro Value Description
CHAR_BIT 8 Defines the number of bits in a byte.
SCHAR_MIN -128 Defines the minimum value for a signed char.
SCHAR_MAX +127 Defines the maximum value for a signed char.
UCHAR_MAX 255 Defines the maximum value for an unsigned char.
CHAR_MIN -128 Defines the minimum value for type char and its value will be equal to SCHAR_MIN if char represents negative values, otherwise zero.
CHAR_MAX +127 Defines the value for type char and its value will be equal to SCHAR_MAX if char represents negative values, otherwise UCHAR_MAX.
MB_LEN_MAX 16 Defines the maximum number of bytes in a multi-byte character.
SHRT_MIN -32768 Defines the minimum value for a short int.
SHRT_MAX +32767 Defines the maximum value for a short int.
USHRT_MAX 65535 Defines the maximum value for an unsigned short int.
INT_MIN -2147483648 Defines the minimum value for an int.
INT_MAX +2147483647 Defines the maximum value for an int.
UINT_MAX 4294967295 Defines the maximum value for an unsigned int.
LONG_MIN -9223372036854775808 Defines the minimum value for a long int.
LONG_MAX +9223372036854775807 Defines the maximum value for a long int.
ULONG_MAX 18446744073709551615 Defines the maximum value for an unsigned long int.

例

以下示例显示了limits.h文件中定义的几个常量的用法。

现场演示

#include 
#include 

int main() {

   printf("The number of bits in a byte %d\n", CHAR_BIT);

   printf("The minimum value of SIGNED CHAR = %d\n", SCHAR_MIN);
   printf("The maximum value of SIGNED CHAR = %d\n", SCHAR_MAX);
   printf("The maximum value of UNSIGNED CHAR = %d\n", UCHAR_MAX);

   printf("The minimum value of SHORT INT = %d\n", SHRT_MIN);
   printf("The maximum value of SHORT INT = %d\n", SHRT_MAX); 

   printf("The minimum value of INT = %d\n", INT_MIN);
   printf("The maximum value of INT = %d\n", INT_MAX);

   printf("The minimum value of CHAR = %d\n", CHAR_MIN);
   printf("The maximum value of CHAR = %d\n", CHAR_MAX);

   printf("The minimum value of LONG = %ld\n", LONG_MIN);
   printf("The maximum value of LONG = %ld\n", LONG_MAX);
  
   return(0);
}

让我们编译并运行上面的程序，它将产生以下结果-

The number of bits in a byte 8
The minimum value of SIGNED CHAR = -128
The maximum value of SIGNED CHAR = 127
The maximum value of UNSIGNED CHAR = 255
The minimum value of SHORT INT = -32768
The maximum value of SHORT INT = 32767
The minimum value of INT = -2147483648
The maximum value of INT = 2147483647
The minimum value of CHAR = -128
The maximum value of CHAR = 127
The minimum value of LONG = -9223372036854775808
The maximum value of LONG = 9223372036854775807