C style array with C++?

Question

I have read many answers on stackoverflow and codereview that says we should not use C style arrays with C++. What is reason for it ? If I use std::Array instead of C style array, will it impact on speed/performance ?

In my organization, entire application is written in C++. But only C style arrays are used.

Theoretically there's no penalty using `std::array` over a C-style array, and practically I doubt it as well (as long as you don't pass the array *by value*, which is possible with `std::array` but not with a C-style array). — Some programmer dude, Sep 23 '19 at 11:36
@Someprogrammerdude In C I can create variable length array at runtime like `int arr[n]`. Is it possible with std::array ? — K_peanutButter, Sep 23 '19 at 11:41

Kostya Regent · Answer 1 · 2019-09-23T12:17:19.140

1

No, it will not have impact on performance. There are two reasons to use std::array instead C-like arrays:

Method at() that allows to get an element by index with bounds checking. Beware, operator [] doesn't have bounds checking.
Limited pointer arithmetic. It's much harder to shoot in the foot than with C-like arrays.
Same behavior as other std containers, like begin(), end(), size() methods without necessity to handle two variables: pointer and size. So, you can implement one algorithm that can work with arrays and other containers.

Thanks Thomas Sablik for clarification in comments.

edited Sep 23 '19 at 12:17

answered Sep 23 '19 at 11:40

Kostya Regent

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@ThomasSablik Yes, but the problem with simple C-style arrays is that they too often decay to pointers, and then `std::begin()` and `std::end()` won't work very well. – Some programmer dude Sep 23 '19 at 11:48

C style array with C++?

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