在C,是两者的区别: ++我和我++ ,并应在使用一个为循环的增量块?
In C, what is the difference between using ++i and i++, and which should be used in the incrementation block of a for loop?
推荐答案-
++我将递增 i的值,然后返回增加后的值。
++i will increment the value of i, and then return the incremented value.
i = 1; j = ++i; (i is 2, j is 2)-
我++ 将递增 i的值,但返回的原始值 I 递增之前举行。
i++ will increment the value of i, but return the original value that i held before being incremented.
i = 1; j = i++; (i is 2, j is 1)
对于为循环,无论是作品。 ++我似乎更常见,可能因为这是在 K&放大器使用; - [R 。
For a for loop, either works. ++i seems more common, perhaps because that is what is used in K&R.
在任何情况下,按照指引preFER ++我在 i ++ ,你赢了T出问题。
In any case, follow the guideline "prefer ++i over i++" and you won't go wrong.
有一个关于 ++我和我++ 的效率夫妇的意见。在任何非学生项目的编译器,将不会有性能差异。您可以通过查看生成的code,这将是相同的验证。
There's a couple of comments regarding the efficiency of ++i and i++. In any non-student-project compiler, there will be no performance difference. You can verify this by looking at the generated code, which will be identical.
效率问题是有趣......这里是我的上述问题的回答:是否有性能差异之间我++和++我用C?
The efficiency question is interesting... here's my attempt at an answer: Is there a performance difference between i++ and ++i in C?
作为的在弗氏的笔记,它是一个C ++对象不同,因为符++()是一个函数,编译器无法知道优化掉临时对象的创建来保存中间值。
As On Freund notes, it's different for a C++ object, since operator++() is a function and the compiler can't know to optimize away the creation of a temporary object to hold the intermediate value.
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有什么区别++ i和i ++的区别
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