add hw2

node_modules/netmask/example/ipcalc.coffee

@@ -0,0 +1,17 @@
+Netmask = require('netmask').Netmask
+
+ip = process.argv[2]
+netmask = new Netmask(ip)
+
+out = console.log
+out "Address: #{ip.split('/', 1)[0]}"
+out "Netmask: #{netmask.mask} = #{netmask.bitmask}"
+out "Wildcard: #{netmask.hostmask}"
+out "=>"
+out "Network: #{netmask.base}/#{netmask.bitmask}"
+out "HostMin: #{netmask.first}"
+out "HostMax: #{netmask.last}"
+out "Broadcast: #{netmask.broadcast}"
+out "Hosts/Net: #{netmask.size}"
+
+out netmask.next()