Reverse iteration with an unsigned loop variable

Personally I have come to like:

for (size_t i = n; i --> 0 ;)

It has a) no funny -1, b) the condition check is mnemonic, c) it ends with a suitable smiley.

Unsigned integers are guaranteed to wrap around nicely. They just implement arithmetic modulo 2^N. So an easy to read idiom is this one:

for (size_t i = n-1; i < n ; --i) { ... }

this sets the variable to the initial value that you want, shows the sense of the iteration (downward) and gives precisely the condition on the values that you want to handle.