Home/ Questions/Q 44111
In Process

The Archive Base Latest Questions

Editorial Team
  • 0
Asked: 2026-05-10T15:36:04+00:00

What’s the best practice for using a switch statement vs using an if statement

  • 0

What’s the best practice for using a switch statement vs using an if statement for 30 unsigned enumerations where about 10 have an expected action (that presently is the same action). Performance and space need to be considered but are not critical. I’ve abstracted the snippet so don’t hate me for the naming conventions.

switch statement:

// numError is an error enumeration type, with 0 being the non-error case // fire_special_event() is a stub method for the shared processing  switch (numError) {     case ERROR_01 :  // intentional fall-through   case ERROR_07 :  // intentional fall-through   case ERROR_0A :  // intentional fall-through   case ERROR_10 :  // intentional fall-through   case ERROR_15 :  // intentional fall-through   case ERROR_16 :  // intentional fall-through   case ERROR_20 :   {      fire_special_event();   }   break;    default:   {     // error codes that require no additional action   }   break;        }

if statement:

if ((ERROR_01 == numError)  ||     (ERROR_07 == numError)  ||     (ERROR_0A == numError)  ||      (ERROR_10 == numError)  ||     (ERROR_15 == numError)  ||     (ERROR_16 == numError)  ||     (ERROR_20 == numError)) {   fire_special_event(); }
Share

Leave an answer

You must login to add an answer.

Need An Account,

1 Answer

  1. Use switch.

    In the worst case the compiler will generate the same code as a if-else chain, so you don’t lose anything. If in doubt put the most common cases first into the switch statement.

    In the best case the optimizer may find a better way to generate the code. Common things a compiler does is to build a binary decision tree (saves compares and jumps in the average case) or simply build a jump-table (works without compares at all).

    • 0