That's old school Basic. For i = 0 to 1000 is telling the proggie to start counting at 0 and stop at 1000. The func... statement has the proggie calculating each number it sees. Next i is telling the proggie move forward to the next number in the sequence....

(i.e., Start counting at 0, perform calculations, move on to next number (1,2,3,4,5...1000) )

Since 'for' is 0 to 1000 - it automatically stops at 1000.

...at least that's what it used to mean on the 'Trash 80's' (Radio Shack TRS-80 Microcomputer - w/ or w/o monitor)

...yea... i know... I just dated mahsef...