Well, what I mean is that I dont see how in C the conditional is only evaluated once. I dont know enough about how C implements a case statement to say for sure But i dont see how a case statement could be implemented in such a way without adding a lot of code to the statement, which would potentially be far more expensive than converting it to a series of conditionals. For instance something like this

switch (val) {
  case 1 : handle_case1; break;
  case 2 : handle_case2; break;
  case 5 : handle_case5;
  case 10: handle_case10;
  default: handle_default; 
}
[download]

I would guess would get converted to something like

if (val == 1) {
  handle_case1;
} elsif (val == 2) {
  handle_case2;
} else {
  if (val == 5) {
    goto CASE5;
  } elsif (val == 10) {
    goto CASE10;
  } else {
    goto DEFAULT;
  }
CASE5:   handle_case5;
CASE10:  handle_case10;
DEFAULT: handle_default;
}
[download]

Or something like it. I just dont see how it could be handled otherwise. Perhaps the fact that it only operates on ints means that there is a neater optimisation. But if you extend switch to handle strings as it does in pascal then I think the situation becomes even more difficult.

Thanks to the CB for clarifying that switch only handles ints. That issue may make my ruminations on this invalid. I dont know. Id be interested to hear from someone that does. As I said, this issue confuses me. :-)