Add homework 6 starter file

Signed-off-by: kfei <kfei@kfei.net>
Finish homework 6

Signed-off-by: kfei <kfei@kfei.net>
Add project 3 starter files

Signed-off-by: kfei <kfei@kfei.net>
Finish phase 1 to 3 for project 3

Signed-off-by: kfei <kfei@kfei.net>
Finish project 3

Signed-off-by: kfei <kfei@kfei.net>