shivashankar - 11 months ago 58

Ruby Question

How can I convert a hexadecimal number for instance

`'C4D81633'`

`'-992471501'`

`['C4D81633'.scan(/[0-9a-f]{2}/i).reverse.join].pack('H*').unpack('l')`

but the above code is not working well when I give input of length less than 8 characters.

Answer

I found the answer after googling... I add it as a method which is as follows

```
def convert_to_signed_twos_complement(integer_value, num_of_bits)
length = num_of_bits
mid = 2**(length-1)
max_unsigned = 2**length
(integer_value >= mid) ? integer_value - max_unsigned : integer_value
end
hex_to_convert = 'C4D81633'
convert_to_signed_twos_complement(hex_to_convert.hex, 16)
Note: the num_of_bits in method denote the max bit size of the binary you want
```