line 15: you need to put something between || and <
line 20: you missed closen parenthesis.
line 19 (and other ones): I strongly recommend you to use parentheses to make sure that the order of operators is right.
and line 12: 3 <= 4 will be true actually
lines 2, 13, 14, 16, 17, 18, 19: comment also wrong