我++，I = I + 1和i + = 1哪一个是更快？ [英] i++, i=i+1 and i+=1 which one is faster?

问题描述

我很好奇，想知道哪一个是在CPU中运行最快的I ++ ， I + = 1 和 I = I + 1 ，我怎么能衡量他们的执行时间？

I'm very curious to know which one is run fastest in the CPU among i++, i+=1 and i=i+1 and how can I measure their execution time?

推荐答案

好了，起初人类发明了以下记录。

Well, at first the mankind invented the following record.

i = i+1; 

然后在硬件个成就沿着mainkind发明了以下记录

then along with achievments in hardware the mainkind invented the following record

i += 1;

和在最后由于在计算机科学的进展人类发明以下记录

and at last due to the progress in the computer sciences the mankind invented the following records

++i;

和

i++;

所有这三种形式的记录是相同的一组的机器指令的前pressions（与++时，他们是一些比较复杂的前pression的部件i和i ++一个次要的例外）:)而这组机器指令不会对编译器优化的水平，甚至依赖。）

All these three forms of records are expressions of the same set of machine instructions.(with a minor exception for ++i and i++ when they are parts of some more complex expression):) And this set of machine instructions does not depend even on the level of the compiler optimization.:)

P.S。当然，我们正在讨论这些运营商为基本类型。没有任何意义，讨论这些运营商为用户定义的类型，因为它们可以以各种方式被重载。

P.S. Of course we are discussing these operators for fundamentals types. There is no any sense to discuss these operators for user-defined types because they can be overloaded in various ways.

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