i— and i = i-1 not evaluating the same

Question

I thought that i-- is a shorthand for i = i - 1, but I discovered that both evaluate different:

Answer 1

i-- is not the same as i=i-1, when used in a loop.

i-- will be evaluated after the condition, but before the loop contents are run, whereas i=i-1 will be evaluated before the condition, so will evaluate to false.

I guess in that respect --i is more similar to i=i-1, as it is also evaluated prior to the condition.

You can think of

while (i--) {...}

As being equivalent to

while (i = i - 1, i + 1) {...}