访问矢量对象的最佳方法 [英] Best way to access vector objects

问题描述

如果我有矢量，

std::vector<int> MyVector;

并且想要访问该向量的第n个元素，我可以通过许多不同的方式进行访问:

And want to access the n'th element of that vector, I can do so in many different ways:

int x = MyVector[n];

或

int x = MyVector.at(n);

甚至使用我不熟悉的迭代器.

or even using iterators that I am not familiar with.

我敢肯定，还有更多的方法可以访问向量中的对象.我要问的是，每种方法的优缺点是什么，因此，如果有的话，哪种方法是最佳"方法.

I am sure there are also many more ways in which a object in a vector can be accessed. What I am asking is, what are the pro's and cons of each and therefore which method would be the "best" if any.

还有，其中任何一个有什么安全的好处?如果不是，为什么有人会在[x]上使用.at(x)?

Also, is there any saftey benifets of any of these? If not why would anyone use .at(x) over [x]?

推荐答案

tl; dr 答案:

各自的优点和缺点是什么[?]

what are the pro's and cons of each[?]

• []不进行边界检查，即不安全和稍快.
• at进行边界检查，即更安全，并且稍慢.
• [] doesn't do bounds-checking, i.e. it is unsafer and slightly faster.
• at does bounds-checking, i.e. it is safer and slightly slower.

好的经验法则:如果性能不是问题，请使用at，否则请使用[].

Good rule of thumb: If performance is not a problem, use at, otherwise, use [].

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