hoge = malloc(length * sizeof struct hage *);
hoge = malloc(sizeof struct hage * * length);
hoge = malloc(*length * sizeof struct hage *);
hoge = malloc(sizeof struct hage * * *length);
hoge = malloc(*length * sizeof struct hage **);
hoge = malloc(sizeof struct hage ** * *length);
()付けないとどんどんわかりにくくなっていく