Very good.

A pet peeve is that it consistently says "sizeof()", like this:

You can use the sizeof() operator to determine how many bytes of memory a certain type uses. (I know, sizeof() looks more like a function than an operator, but there we are.)

BUT: sizeof does not in fact need the parentheses always!

Syntactically they are part of the argument, and only needed when the argument is a type name, i.e. the argument looks like a cast to that type.

So:

    int x;
    printf("%zu == %zu\n", sizeof x, sizeof (int));

It's very annoying to see the guide kind of glance off the way things really are, into confusion.

Very glad to see it doesn't cast the return value of malloc(), too. :)