Question: ```
WaveTrack *track = (WaveTrack *) iter.First();

```

I don't understand about the meaning of blanket here. It would be nicer if somebody can explain more about the meaning of whole code sentence.

Answer: 
It initializes a `WaveTrack` pointer with the value of `iter.First()`. The `(WaveTrack*)` is a C-style cast. If `iter.First()` returns a different type of pointer, it will be cast to a `WaveTrack` pointer.
If the word "blanket" means "space" in your question, then I would say that it is here for readability.

Too much code compression makes it difficult to understand.

In a language like C or C++, where pointers are used frequently, it is crucial to write things clear and each type cast must be visible.