Casting double to ulong weirdness

[rumbu via Digitalmars-d]

BTW, 1.2 and 12.0 are directly representable as double

In C++:

printf("%.20f\r\n", 1.2);
printf("%.20f\r\n", 12.0);

will output:

1.20000000000000000000
12.00000000000000000000

Either upcasting to real is the wrong decision here, either the 
writeln string conversion is wrong.