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cypherpunks01
Is this supposed to reveal something insightful about switch statements in C?
theonewolf
That you can compile with with labels instead of _any_ actual case statements :-) although your source, at a cursory glance, looks like it has valid cases defined.
dmbass
Maybe if you've never written C before...
dllthomas
This is why you compile with -Wall and -Werror...
bichiliad
Don't you need to say "case" before every case statement?
theonewolf
Precisely the issue, very easy to miss, still compiles, looks normal.
_ZeD_ 

    $ echo $CFLAGS
    -Werror -Wall -Wextra -Wold-style-definition -Wmissing-declarations -Wredundant-decls -Wmissing-noreturn -Wshadow -Wpointer-arith -Wcast-align -Wwrite-strings -Winline -Wformat-nonliteral -Wformat-security -Wswitch-enum -Wswitch-default -Winit-self -Wmissing-include-dirs -Wundef -Waggregate-return -Wmissing-format-attribute -Wnested-externs -std=c11 -pedantic
theonewolf
Nice safer CFLAGS :-) But yeah, that's why this is a "brain teaser" rather than a "compiler teaser." It's not that it _can't_ be caught with a compiler, just that it's easy to miss and acceptable to compilers with default flags.
Denzel
Not really a brain teaser: the only case being the default, and the rest simply being labels, makes for a very straightforward program.
theonewolf
Right, the point being that you can compile an "almost correct"-looking switch statement with labels instead of actual case statements.
matthavener
Every time I forget to type "case " I'm instantly corrected when my editor (rightly) removes all indentation and puts the label on the leftmost column.
theonewolf
vim? My editor does this too thank God :-)
bitbckt
-Wswitch-enum
_ZeD_
-Werror=switch-enum -Werror=unused-label

(but you get the point :D)

theonewolf
that's why it's a "Brain teaser" and not a "compiler teaser."

If you were inspecting code without a compiler it's easier to miss.

The standard '-Wall -Werror' catches it (arguably, it'd be nice if everyone _at least_ did -Wall by default).

nikbackm
How obvious!

And yet I missed it :(