To learn how to script.

[John]

You use while and do...while for conditional looping (you don't know how many times you have to loop). You use switch when you wanna compare 1 variable to a bunch of values (could also be done with a bunch of if...else if). You use break if you want to exit a loop early (I usually put those with a condition). You use return; when you want to exit a function early. I could give you java syntax, but you probably don't want that.

He doesn't really need do{}, I even doubt anyone uses it on graal anyways: (if it works)

do {
  echo(temp.i);
  temp.i++;
} while (temp.i <=5);