Question

I was looking over this code to calculate math.sqrt in Java. Why did they use hex values in some of the loops and normal values for variables? What benefits are there to use hex?

Answer 1

Because hex corresponds much more closely to bits that decimal numbers. Each hex digit corresponds to 4 bits (a nibble). So, once you’ve learned the bitmask associated with each hex digit (0-F), you can do something like ‘I want a mask for the low order byte’:

0xff 

or, ‘I want a mask for the bottom 31 bits’:

0x7fffffff 

Just for reference:

HEX    BIN 0   -> 0000 1   -> 0001 2   -> 0010 3   -> 0011 4   -> 0100 5   -> 0101 6   -> 0110 7   -> 0111 8   -> 1000 9   -> 1001 A   -> 1010 B   -> 1011 C   -> 1100 D   -> 1101 E   -> 1110 F   -> 1111