Does the last element in a loop deserve a separate treatment?
control-structure, for-loop, language-agnostic, loops, while-loop
Solution
@xtofl,
I agree with your concern.
Million times I encountered similar problem.
Either developer adds special handling for first or for last element.
In most cases it is worth to just loop from startIdx + 1 or to endIdx - 1 element or even split one long loop into multiple shorter loops.
In a very rare cases it's not possible to split loop.
In my opinion uncommon things should be handled outside of the loop whenever possible.
Problem
When reviewing, I sometimes encounter this kind of loop: ``` i = begin while ( i != end ) { // ... do stuff if ( i == end-1 (the one-but-last element) ) { ... do other stuff } increment i } ``` Then I ask the question: would you write this? ``` i = begin mid = ( end - begin ) / 2 // (the middle element) while ( i != end ) { // ... do stuff if ( i > mid ) { ... do other stuff } increment i } ``` In my opinion, this beats the intention of writing a loop: you loop because there is something common to be done for each of the elements. Using this construct, for some of the elements you do something different. So, I conclude, you need a separate loop for those elements: ``` i = begin mid = ( end - begin ) / 2 //(the middle element) while ( i != mid ) { // ... do stuff increment i } while ( i != end ) { // ... do stuff // ... do other stuff increment i } ``` Now I even saw a question on SO on how to write the `if`-clause in a nice way... And I got sad: something isn't right here. Am I wrong? If so, what's so good about cluttering the loop body with special cases, which you are aware of upfront, at coding time?