整数的最大值

Question

在C中，整数（对于32位机器）是32位，其范围从-32,768到+32,767。在Java中，整数也是32位，但范围从-2,147,483,648到+2,147,483,647。

我不明白Java中的范围是如何不同的，即使位数是相同的。有人可以解释一下吗？

Answer 1

在C语言中，语言本身并不确定某些数据类型的表示形式。它可以因机器而异，在嵌入式系统上int可以是16位宽，但通常是32位。唯一的要求是short int<= int<= long int按大小。此外，还有一个建议int应该代表处理器的本机容量。所有类型都签名。该unsigned修改器允许您使用最高位的值（否则它被保留为符号位）的一部分。以下是可能的数据类型的可能值的简短表：&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; width&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;minimum&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;maximumsigned&nbsp; &nbsp; 8 bit&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; -128&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; +127signed&nbsp; &nbsp;16 bit&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;-32 768&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;+32 767signed&nbsp; &nbsp;32 bit&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; -2 147 483 648&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; [phone]signed&nbsp; &nbsp;64 bit&nbsp; -9 223 372 036 854 775 808&nbsp; &nbsp; &nbsp; [phone] 775 807unsigned&nbsp; 8 bit&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;0&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; +255unsigned 16 bit&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;0&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;+65 535unsigned 32 bit&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;0&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; [phone]unsigned 64 bit&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;0&nbsp; &nbsp; &nbsp;[phone] 551 615在爪哇，在Java语言规范确定的数据类型的表示。顺序是：byte8位，short16位，int32位，long64位。所有这些类型都是签名的，没有未签名的版本。但是，位操作会将数字视为无符号（即正确处理所有位）。字符数据类型char是16位宽，无符号，并使用UTF-16编码保存字符（但是，可以分配一个char表示无效字符代码点的任意无符号16位整数）&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; width&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;minimum&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;maximumSIGNEDbyte:&nbsp; &nbsp; &nbsp;8 bit&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; -128&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; +127short:&nbsp; &nbsp;16 bit&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;-32 768&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;+32 767int:&nbsp; &nbsp; &nbsp;32 bit&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; -2 147 483 648&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; [phone]long:&nbsp; &nbsp; 64 bit&nbsp; -9 223 372 036 854 775 808&nbsp; &nbsp; &nbsp; [phone] 775 807UNSIGNEDchar&nbsp; &nbsp; &nbsp;16 bit&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;0&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;+65 535

Answer 2

在C中，整数（对于32位机器）是32位，其范围从-32768到+32767。错误。以2的补码表示的32位有符号整数的范围为-2 31到2 31 -1，等于-2,147,483,648到2,147,483,647。