for q.1 learn the bodmas rule and remember || is the expression for "or" and so work out the meaning for the expressions on the either side of it seperately and use logic of "or".
q.2 b. cant you compile and run your own program. as for sec.b read about ascii values and use int data type; if ur code doesnt work out.
q.3 think which program uses more checking, that should be worse.
q.4 there is nothing to tell..
