for(i = length - 1; i < SIZE_MAX ; i--)
but it is completely valid.
The only people I would not want to work with are ignoramuses and ironically, smart-asses. So you.
for(i = 0; i < length; i++) .. do something with (length - i - 1) ..
for (i = 0; i <= length; i++) .. boy I sure hope length is not a max value ..
for(i = length - 1; i < SIZE_MAX ; i--)
but it is completely valid.