Something like... (Pseudocode)

    for( i= 1,100 )
    {
      if( i%3==0 ) { print( 'Fizz' ) }
      if( i%5==0 ) { print( 'Buzz' ) }
      print( '\n' )
    }

There's no need to treat FizzBuzz as a special case, as if the number is divisible by both it will have already met the conditions of the previous two statements.

I wonder if there's some magic you could sprinkle in to the iterator so it only iterates through numbers which are divisible by 3/5, ignoring the rest?

It probably wouldn't speed the operation up much (if at all) in this case, in a more complex real world scenario though it's best to look at every angle.

You haven't printed any of the other numbers. Read the spec more carefully. You still need to print 1, 2, 4, etc.