[fix] fixes calculate tip syntax error and changes print to use function form
[fix] fixes calculate tip syntax error and changes print to use function form

marksanghoonkim/nimblecode,rickyeh/nimblecode,rickyeh/nimblecode,marksanghoonkim/nimblecode,nimblecode/nimblecode,nimblecode/nimblecode,LinearAtWorst/cogile,marksanghoonkim/nimblecode,LinearAtWorst/cogile,nimblecode/nimblecode,rickyeh/nimblecode,marksanghoonkim/nimblecode,nimblecode/nimblecode,rickyeh/nimblecode