As a puzzle, commenter nobugz
asks,
"What kind of infinity is 1.#J?"
double z = 0;
printf("%.2f", 1/z);
Now, the division by zero results in IEEE positive infinity,
would would normally be printed as
1#INF.
But the catch here is that the print format says
"Display at most two places after the decimal point."
But where is the decimal point...