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飞天御剑流 2009-07-13
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[Quote=引用楼主 bestoak 的帖子:]
请问既然定义了是无符号，为什么k还可以等于-1呢？
[/Quote]
这不是k等于-1，标准规定，进行整形转换的时候，如果新值是无符号类型，当旧值不在新值的表示范围内时，会将旧值加上新值无符号类型的最大值再加一，再
赋予新值，标准摘录如下：
6.2.1.2 Signed and unsigned integers
When a value with integral type is converted to another integral type, if the value can be
represented by the new type, its value is unchanged.
When a signed integer is converted to an unsigned integer with equal or greater size, if the
value of the signed integer is nonnegative. its value is unchanged. Otherwise: if the unsigned
integer has greater size, the signed integer is first promoted to the signed integer corresponding to
the unsigned integer: the value is converted to unsigned by adding to it one greater than the
largest number that can be represented in the unsigned integer type ”
请问既然定义了是无符号，为什么k还可以等于-1呢？
[/Quote]
这不是k等于-1，标准规定，进行整形转换的时候，如果新值是无符号类型，当旧值不在新值的表示范围内时，会将旧值加上新值无符号类型的最大值再加一，再
赋予新值，标准摘录如下：
6.2.1.2 Signed and unsigned integers
When a value with integral type is converted to another integral type, if the value can be
represented by the new type, its value is unchanged.
When a signed integer is converted to an unsigned integer with equal or greater size, if the
value of the signed integer is nonnegative. its value is unchanged. Otherwise: if the unsigned
integer has greater size, the signed integer is first promoted to the signed integer corresponding to
the unsigned integer: the value is converted to unsigned by adding to it one greater than the
largest number that can be represented in the unsigned integer type ”
风老二 2009-07-12
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[Quote=引用楼主 bestoak 的帖子:]
请问既然定义了是无符号，为什么k还可以等于-1呢？
[/Quote]
可以理解为int与uint都在一个容器里，只不过解析方法不同
请问既然定义了是无符号，为什么k还可以等于-1呢？
[/Quote]
可以理解为int与uint都在一个容器里，只不过解析方法不同
haierpro 2009-07-12
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同意二楼的说法，应该是自动类型转换，就像int a = 'c';
AlwaysSLH 2009-07-12
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学习一下：原码、反码、补码，以及数在计算机中的表示
happypeter2008 2009-07-12
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有点玄乎
东大坡居士 2009-07-12
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无所谓符号了~~~~
lemirymoo 2009-07-12
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看淡一些吧，其实无所谓符号，也无所谓数值，用的时候你怎么去用它就是什么。
printf("1.k=%d",k);
printf("2.k=%u",k);
k = 1145258561;
printf("3.k=%s",&k);
printf("1.k=%d",k);
printf("2.k=%u",k);
k = 1145258561;
printf("3.k=%s",&k);
ljhhh0123 2009-07-12
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假如unsigned long 是32位长度,-1就是0xffffffff,这两个表示方法没什么区别.
把这个值传过去,编译器假设你知道自己在做什么.
把这个值传过去,编译器假设你知道自己在做什么.
Walf_ghoul 2009-07-12
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无符号不是所看见的，关键得理解里面的二进制存储。。
blh 2009-07-12
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[Quote=引用楼主 bestoak 的帖子:]
请问既然定义了是无符号，为什么k还可以等于-1呢？
[/Quote]
自动类型转换
请问既然定义了是无符号，为什么k还可以等于-1呢？
[/Quote]
自动类型转换
