Calculate broadcast address from ip and subnet mask

Question

I want to calculate the broadcast address for:

IP:     192.168.3.1
Subnet: 255.255.255.0
=       192.168.3.255

in C.

I know the way

Answer 1

Just calculate:

broadcast = ip | ( ~ subnet )

(Broadcast = ip-addr or the inverted subnet-mask)

The broadcast address has a 1 bit where the subnet mask has a 0 bit.