Java - curious number declaration

Question

I have found somewhere a pretty weird number declaration in Java.

double x = 0xap-001;

I am curious why the value of x is 5.0

Answer 1

p indicates a binary exponentiation. So you have hex 0xa == 10, with a binary exponent of -1 - in other words a shift right or div 2. The result is 10/2 = 5.