finished tour17

Signed-off-by: Kouhei Maeda <mkouhei@palmtb.net>
finished tour18

Signed-off-by: Kouhei Maeda <mkouhei@palmtb.net>
finished tour19

Signed-off-by: Kouhei Maeda <mkouhei@palmtb.net>
finished tour20

Signed-off-by: Kouhei Maeda <mkouhei@palmtb.net>
finished tour21

Signed-off-by: Kouhei Maeda <mkouhei@palmtb.net>
finished tour22

Signed-off-by: Kouhei Maeda <mkouhei@palmtb.net>
finished tour23

Signed-off-by: Kouhei Maeda <mkouhei@palmtb.net>
fixed using fmt.Println instead of fmt.Printf

Signed-off-by: Kouhei Maeda <mkouhei@palmtb.net>