Programming Puzzler

Quick test for all you programming experts. Will this stupid code compile?

public int InfiniteLoop()
{
    while (true)
    {
        Console.WriteLine("Loopy");
        System.Threading.Thread.Sleep(1000);
    }
}

Note: All the namespaces are in place and the WriteLine and the Sleep are perfectly legal calls.

Update on Thursday, February 24, 2011 at 05:54PM by Rob

Turns out that it compiles just fine. The compiler is smart enough to work out that the method will never complete because it contains an infinite loop. This means that although the signature of InfiniteLoop defines it as returning an integer the compiler just says "Since the method never ends I'm not going to worry about it not returning a value when it says it should".

I'm not sure I agree with this behaviour. I saw it in the lab this morning and it surprised me. I would expect at least a warning, in case I'd put a loop in when I didn't mean to. 

The compiler doesn't fail to compile programs containing unreachable code either, although this does produce a warning.

Comments

[Erik SIjnja]

No, there is no return for the int required

[Sid]

Yes, there is no need for a return if the function does not end

[Benjamin]

It would not compile because the function is supposed to return an integer type, but does not do that in the function, if it was a void function then it would run an infinite loop which stops every 1000th of a second

[Benjamin]

If there was a return line of code, the complier will flag an error saying line of code unreachable, because it would never get to the return until the program is forcefully terminated.

[Alfred Thompson]

Well it did for me. :-) I had to make it static to call it from main() though.

[Erik Sijnja]

@Sid: U R so right.

[Alice]

what's the answer ?

[James]

Probably give a warning on the int return :)

[Jay Wakefield]

would the fact it doesny compile that bit of code not cause a runtime error later on?