How to call a function every x seconds but be able to do stuff in the meantime

I'm building a tetris game and I need the pieces to fall every x seconds; something like:

while(true){
  moveDown();
  sleep(x)
}

The problem is, I need to be able to move the pieces left and right in the meantime, i.e., call a function while it's sleeping.

How can I do that in c++?

This problem is solvable in multiple ways (another idea that comes to mind is multithreading, but that seems overkill). One approach would be to keep track of the number of "game cycles" and execute some function every n-th cycle like this:

for(int32_t count{1};;count++)
{
    if (!count % 5)
    {
        // do something every 5th cycle
    }
    // do something every cycle
    sleep(x);
}