Switch statement with returns — code correctness

Question

Let\'s say I have code in C with approximately this structure:

switch (something)
{
    case 0:
      return \"blah\";
      break;

    case 1:
    case 4:
         


        

Answer 1

I would remove them. In my book, dead code like that should be considered errors because it makes you do a double-take and ask yourself "How would I ever execute that line?"

Answer 2

I would say remove them and define a default: branch.

Answer 3

I would take a different tack entirely. Don't RETURN in the middle of the method/function. Instead, just put the return value in a local variable and send it at the end.

Personally, I find the following to be more readable:

String result = "";

switch (something) {
case 0:
  result = "blah";
  break;
case 1:
  result = "foo";
  break;
}

return result;

Answer 4

Exit code at one point. That provides better readability to code. Adding return statements (Multiple exits) in between will make debugging difficult .

Answer 5

Interesting. The consensus from most of these answers seems to be that the redundant break statement is unnecessary clutter. On the other hand, I read the break statement in a switch as the 'closing' of a case. case blocks that don't end in a break tend to jump out at me as potential fall though bugs.

I know that that's not how it is when there's a return instead of a break, but that's how my eyes 'read' the case blocks in a switch, so I personally would prefer that each case be paired with a break. But many compilers do complain about the break after a return being superfluous/unreachable, and apparently I seem to be in the minority anyway.

So get rid of the break following a return.

NB: all of this is ignoring whether violating the single entry/exit rule is a good idea or not. As far as that goes, I have an opinion that unfortunately changes depending on the circumstances...

Answer 6

I personally tend to lose the breaks. Possibly one source of this habit is from programming window procedures for Windows apps:

LRESULT WindowProc (HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
    switch (uMsg)
    {
        case WM_SIZE:
            return sizeHandler (...);
        case WM_DESTROY:
            return destroyHandler (...);
        ...
    }

    return DefWindowProc(hwnd, uMsg, wParam, lParam);
}

I personally find this approach a lot simpler, succinct and flexible than declaring a return variable set by each handler, then returning it at the end. Given this approach, the breaks are redundant and therefore should go - they serve no useful purpose (syntactically or IMO visually) and only bloat the code.