What does this strange code do?

Question

I found this weird code on the net but can't figure out what it does. When I compile it I don't get any output.

int main()<%auto f = <::><%%>;%>

See here: https://en.wikipedia.org/wiki/Digraphs_and_trigraphs — clcto, Mar 16 '15 at 16:38
"What does this strange code do?" -- mark the author as quite the prankster. :-D — DevSolar, Mar 16 '15 at 16:39

score 12 · Answer 1 · answered Mar 16 '15 at 16:39

Using digraphs, <% corresponds to {, and %> corresponds to }.

Substituting these in yields

int main(){ auto f = <::>{}; }

Finally, <: is equivalent to [ and :> to ], so we end up with

int main(){ auto f = []{}; }

where []{} is an empty lambda, and f is a copy of the closure object.

score 6 · Answer 2 · answered Mar 16 '15 at 16:39

6

It uses digraphs to obfuscate some simple code. It is exactly the same as

int main() { auto f = []{}; }

In other words, not much. It just instantiates an empty lambda, binding it to f. f isn't even called.

answered Mar 16 '15 at 16:39

juanchopanza

2 Answers2