Question

The caption pretty much says it.

PS. This is for C++ Windows program.

Answer 1

According to the MSDN documentation on srand() (assuming you are using Microsoft’s C runtime library), the seed is thread-local, so you need to call srand() for each thread that is using rand(). Note that this may not be the case in other implementations.

Quoting from MSDN:

The srand function sets the starting point for generating a series of pseudorandom integers in the current thread.