Seamus/Hogwarts - Prefect

[banjoken at optonline.net]

No: HPFGUIDX 22018

> Dumbledore made James a prefect (and then Head Boy) and James did a 
lot
> more rule-breaking Harry.

Do we know how prefects and head boys/girls are chosen? I don't know 
if it would be just Dumbledore's decision. I would think that at the 
very least the heads of house have some say in who the prefects for 
their house are. Also, when did Dumbledore become headmaster? We know 
that at the time of Tom Riddle, he was just transfiguration teacher. 
Was he headmaster by the time James and Lily were in school?

Ken