Is it necessary to lock an array that is *only written to* from one thread and *only read from* another?

Question

I have two threads running. They share an array. One of the threads adds new elements to the array (and removes them) and the other uses this array (read operations only).

Answer 1

As far as I know, this is exactly the usecase for a lock. Two threads which access one array concurrently must ensure that one thread is ready with its work. Thread B might read unfinished data if thread A did not finish work.