Advantages of using arrays instead of std::vector?

In general, I strongly prefer using a vector over an array for non-trivial work; however, there are some advantages of arrays:

Arrays are slightly more compact: the size is implicit.
Arrays are non-resizable; sometimes this is desirable.
Arrays don't require parsing extra STL headers (compile time).
It can be easier to interact with straight-C code with an array (e.g. if C is allocating and C++ is using).
Fixed-size arrays can be embedded directly into a struct or object, which can improve memory locality and reducing the number of heap allocations needed.

Because C++03 has no vector literals. Using arrays can sometime produce more succinct code.

Compared to array initialization:

char arr[4] = {'A', 'B', 'C', 'D'};

vector initialization can look somewhat verbose

std::vector<char> v;
v.push_back('A');
v.push_back('B');
...

I'd go for std::array available in C++0x instead of plain arrays which can also be initialized like standard arrays with an initializer list

https://en.cppreference.com/w/cpp/container/array

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