On Wednesday, 26 June 2013 at 20:51:35 UTC, Gary Willoughby wrote:
Just for a bit of fun, I saw this question posted on reddit the
other day and wondered how *you* would solve this in D?
http://stackoverflow.com/questions/731832/interview-question-ffn-n
Well, considering there is little to that specification:
int f(int num) {
import std.exception;
static called = false;
enforce(num != int.min);
if(!called) {
called = true;
return num;
} else {
called = false; // Only for unittesting
return -num;
}
}
unittest {
assert(f(f(3)) == -3);
assert(f(f(-3)) == 3);
assert(f(f(int.min+1)) == int.max);
assert(f(f(int.max)) == int.min+1);
}
int having the issue that not all numbers are representable in
both +/-.
