vector with constant size

Question

I am looking for a C++ data type similar to std::vector but without the overhead related to dynamic resizing. The size of the container will remain constant over its lifetime. I considered using boost::array, however, that is not appropriate because it requires the size of the array to be known at compile time, which is not the case in my situation.

Answer 1

Measure if the dynamic resizing has really any performance impact before using anything non-standard.

Tip: With vector.reserve there will never be any array-reallocation.

Answer 2

There's no overhead in reallocation if you don't reallocate std::vector. So either:

• construct the std::vector with a known size ahead (std::vector x(100))
• call reserve(n) after construction to make sure that at least n elements can be pushed into the vector before reallocation occurs.