A girl on irc once asked if there is a way to solve FizzBuzz with just one comparison.
Yours is indeed one and it is pretty clever :)
Here is another one https://gist.github.com/giuseppeg/5939177
#include <stdio.h>
#include <stdlib.h>
int i(const int i) { printf("%d\n", i); return i; }
int f(const int i) { printf("Fizz\n"); return i; }
int b(const int i) { printf("Buzz\n"); return i; }
int fb(const int i) { printf("FizzBuzz\n"); return i; }
int (* PC[15])(int i) = { i,i,f,i,b,f,i,i,f,b,i,f,i,i,fb }; // Printer Cycle
int go(const int arg) {
return PC[(arg - 1) % 15](arg) + 1;
}
int stop(const int arg) {
PC[(arg - 1) % 15](arg);
exit(0);
}
int (* LC[2]) (int index) = { go, stop }; // Logic Cycle
void recurse(const int i, const int kill_num) {
recurse(LC[!(i % kill_num)](i), kill_num);
}
int main(const int argc, const char *argv[]) {
recurse(1, atoi(argv[1]));
}'0' and no number input also crash it.
(Obviously it transforms it to a loop, so it sorta breaks the rules at compile time)
> int (* PC[15])(int i) = { i,i,f,i,b,f,i,i,f,b,i,f,i,i,fb }; // Printer Cycle
> int (* LC[2]) (int index) = { go, stop }; // Logic Cycle
I can see they behave as functions, but I don't understand what exactly are they or the logic that makes then work.
They are both an array of pointers to functions.
Go(int i) is a function that finds the correct "printer" for a number, i, within the cycle of 15. `Go` then calls the printer function with the argument and prints the corresponding line.
Stop(int i) has similar side-effect but exits immediately after.
Since all of the printers return the value of "i", you can recursively call them in cycle-sequence through `go` until the return value lines up with the "kill number" and causes `stop` to be called instead (this works as `i % n > 0` for all numbers below n and you can force this to be zero, and thus index the first element of the array, by negating it).
Sorry for the scatterbrained explanation, the code wasn't designed to be particularly comprehensible!
perl -E 'map { say } map { { 3 => "Fizz", 5 => "Buzz", 15 => "FizzBuzz" }->{ sub { my $val = shift; (grep { $val % $_ == 0 } (3, 5, 15))[-1] }->($_) } || $_ } (1..100)'
map { say }
map {
{ 3 => "Fizz", 5 => "Buzz", 15 => "FizzBuzz" }->{
sub {
my $val = shift;
(grep { $val % $_ == 0 } (3, 5, 15))[-1]
}->($_)
} || $_
} (1..100)words[c] || i
I focused on the bitwise thing and I overlooked that part
Is first expression true? If it isn't evaluate the second expression.
At least it would in C. Of course I'm ignoring the fact that JS is interpreted as will cause a lot of additional bloat, but were not counting that.
In js the for could be replaced with an array of 100 elems and a forEach:
Array.apply(null, { length: 100 }).forEach(function (_, i) { })