Yes. Like I wrote in another comment: authors' expectations and explanations aren't... very convincing. Asking about the order of execution in a concurrent pro

Yes. Like I wrote in another comment: authors' expectations and explanations aren't... very convincing. Asking about the order of execution in a concurrent program which certainly can have multiple valid orders by design is unfair. Also, a lot of discrepancy between results is explained by how long the program waits for spawned but unawaited tasks before exiting. In a realistic program, this situation would be considered a bug (spawning a task w/o awaiting it, and then missing the results because the program exits too soon). I can't imagine a situation where the program's author would intentionally create a situation where non-deterministically, a part of the program might not run...