两晋演义 下载:signed和unsigned的比较

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signed和unsigned的比较

2009-10-25 10:43 766人阅读 评论(0) 收藏 举报

昨天,zrf师兄丢给我这样一个题,据说是微软面试题:

unsigned int i=3;
cout<Type NameBytesOther NamesRange of Valuesint*signed,
signed intSystem dependentunsigned int*unsignedSystem dependent__int81char,
signed char–128 to 127__int162short,
short int,
signed short int–32,768 to 32,767__int324signed,
signed int–2,147,483,648 to 2,147,483,647__int648none–9,223,372,036,854,775,808 to 9,223,372,036,854,775,807char1signed char–128 to 127unsigned char1none0 to 255short2short int,
signed short int–32,768 to 32,767unsigned short2unsigned short int0 to 65,535long4long int,
signed long int–2,147,483,648 to 2,147,483,647unsigned long4unsigned long int0 to 4,294,967,295enum*noneSame as intfloat4none3.4E +/- 38 (7 digits)double8none1.7E +/- 308 (15 digits)long double10none1.2E +/- 4932 (19 digits)
对上表补充说明一下:1)在32位机上,int型和unsigned int型都是32位的(4个字节)。2)enum会跟据最大值来决定类型,一般来说为int型,如果超出int型所能表示的范围,则用比int型大的最小类型来表示(unsigned int, long 或者unsigned long)3)关于类型的大小。一般用所能表示的数据范围来比较类型的大小,如char型 上一篇:cerr 同cout区别与用法