The following code should be considered bad form, regardless of language or desired functionality:
while( true ) {
}
The while( true ) loop is poor form because it:
while(true) for loops that are not infinite, we lose the ability to concisely communicate when loops actually have no terminating condition. (Arguably, this has already happened, so the point is moot.)The following code is better form:
while( isValidState() ) {
execute();
}
bool isValidState() {
return msg->state != DONE;
}
No flag. No goto. No exception. Easy to change. Easy to read. Easy to fix. Additionally the code:
The second point is important. Without knowing how the code works, if someone asked me to make the main loop let other threads (or processes) have some CPU time, two solutions come to mind:
Readily insert the pause:
while( isValidState() ) {
execute();
sleep();
}
Override execute:
void execute() {
super->execute();
sleep();
}
This code is simpler (thus easier to read) than a loop with an embedded switch. The isValidState method should only determine if the loop should continue. The workhorse of the method should be abstracted into the execute method, which allows subclasses to override the default behaviour (a difficult task using an embedded switch and goto).
Contrast the following answer (to a Python question) that was posted on StackOverflow:
while True:
choice = raw_input('What do you want? ')
if choice == 'restart':
continue
else:
break
print 'Break!'
Versus:
choice = 'restart';
while choice == 'restart':
choice = raw_input('What do you want? ')
print 'Break!'
Here, while True results in misleading and overly complex code.