Array.at(index) over Array[index]

Question

I start to learn std::array and found function to access array with .at(index of element). Is there any reason to it over array.[index of element] style?(e.g speed, exception or other).

Did you compare the documentation for those? What did you find out? — Mat, Jul 05 '17 at 07:41
Possible duplicate of [vector::at vs. vector::operator\[\]](https://stackoverflow.com/questions/9376049/vectorat-vs-vectoroperator) — t.niese, Jul 05 '17 at 07:49
I found answer. With .at() it checks boundary of array. Where with [] operator it doesn't. — Jasurbek Nabijonov, Jul 05 '17 at 07:52

score 2 · Accepted Answer · answered Jul 05 '17 at 07:52

Consider (link)

const_reference operator[](size_type pos) const;

and (link)

const_reference at(size_type pos) const;

They both return a reference to the element at the specified location: pos. However, the former does not perform bounds checking, whereas the latter does. In case !(pos < size()) the latter will throw an std::out_of_range exception.

Array.at(index) over Array[index]

1 Answers1