Then you are wrong, since we're already talking about arrays of sizes known at compile time. Indeed, otherwise we would also need to remember the size in the runtime.
People are being very loose about what O(n) means so I attempted to clarify that a bit. Considering what assignments can already do in C it's somewhat irrelevant whether they think it's O(n) anyway, it doesn't actually make their point correct XD
void foo(size_t n) {
int arr[n];
…
}> The type of the entity to be initialized shall be an array of unknown size or a complete object type that is not a variable length array type.
Curiously, C23 actually seems to break the O(1) rule, by allowing VLAs to be initialized with an empty initializer:
int arr[n] = {};
Stupid question: Does that mean a huge value for 'n' can cause stack overflow at runtime? I recall that threads normally get a fixed size stack size, e.g., 1MB.