Using continue in a switch statement

Question

I want to jump from the middle of a switch statement, to the loop statement in the following code:

while (something = get_something()) {     switch (something)     {     case A:     case B:         break;     default:         // get another something and try again         continue;     }     // do something for a handled something     do_something(); } 

Is this a valid way to use continue? Are continue statements ignored by switch statements? Do C and C++ differ on their behaviour here?

Answer 1

It's fine, the continue statement relates to the enclosing loop, and your code should be equivalent to (avoiding such jump statements):

while (something = get_something()) {     if (something == A || something == B)         do_something(); } 

But if you expect break to exit the loop, as your comment suggest (it always tries again with another something, until it evaluates to false), you'll need a different structure.

For example:

do {     something = get_something(); } while (!(something == A || something == B)); do_something(); 

Answer 2

Yes, continue will be ignored by the switch statement and will go to the condition of the loop to be tested. I'd like to share this extract from The C Programming Language reference by Ritchie:

The continue statement is related to break, but less often used; it causes the next iteration of the enclosing for, while, or do loop to begin. In the while and do, this means that the test part is executed immediately; in the for, control passes to the increment step.

The continue statement applies only to loops, not to a switch statement. A continue inside a switch inside a loop causes the next loop iteration.

I'm not sure about that for C++.