More details on the ISO C++ blog about runtime-sized arrays in C++14.
N3639 proposes to add local runtime-sized arrays with automatic storage duration to C++, for example:
void f(std::size_t n)
for (std::size_t i = 0; i < n; ++i)
a[i] = 2*i;
Traditionally, the array bound “n” had to be a constant expression.