$ make
$ ./main 8890
use curl to get response:
$ curl 127.0.0.1:8890
# <!DOCTYPE html>
# <html><body><div>You are using GET method.</div></body></html>
$ curl -X WHATEVER 127.0.0.1:8890
# <!DOCTYPE html>
# <html><body><div>You are using WHATEVER method.</div></body></html>