🔒 Locked

Your indirect history lesson for the day

Started by Sneftel Mar 26, 2011 at 9:07 PM 5 replies 1k views

Original Post

Mar 26, 2011 at 9:07 PM


 #include <cstdio>
 using namespace std;
 
 #define SECRET(x) 0[#x]
 
 int main()
 {
 printf("%c\n", SECRET([));
 printf("%c\n", SECRET(??());
 printf("%c\n", SECRET(<<img src='http://public.gamedev.net/public/style_emoticons/<#EMO_DIR#>/smile.gif' class='bbc_emoticon' alt=':)' />);
 }

Discuss.

ApochPiQ

Mar 26, 2011 at 9:10 PM

So... you're abusing trigraphs, stringification operators in macros, and the array-index/index-array isomorphism in C/C++ syntax.

Aside from the obvious tools of evil, what are we supposed to glean from this?

Antheus

Mar 26, 2011 at 9:13 PM

[][

If I'm reading the commutativity and trigraphs right.

Sneftel

Mar 26, 2011 at 9:14 PM

Hey, trigraphs have bitten more than one programmer who commented


 // Why isn't this printing???????????/
 printf("hello, world!\n");

BTW, the output of the last line should surprise you.

sprite_hound

Mar 26, 2011 at 9:57 PM

[[<
Why aren't you using std::cout?

Sneftel

Mar 26, 2011 at 10:04 PM

Because whatever.

Actually, the whole thing can be put more succinctly:


 
 #include <cstdio>
 using namespace std;
 
 int main()
 {
 char secret <:??) = "<:??)";
 printf("%s\n", secret);
 }

(Incidentally, that formulation illustrates a distinct incompatibility of Visual C++, whereas the original one just happens to compile. To compile this one, disable language extensions in the project properties window.)

owl

Mar 26, 2011 at 11:19 PM

Trigraphs seem to be disabled by default on MinGW. "warning: trigraph ??( ignored, use -trigraphs to enable". And if you enable them it will warn about convertions.

Topic Locked

This topic has been locked by a moderator. New replies are not allowed.