Question

hello I have some question about java, why the following code return strange value?

System.out.println("Strange " + (20 * 232792560)/20);

why do I recieve 18044195?

Answer 1

Because (20 * 232792560) overflows the range of an int, and wraps round the number range several times to become 360883904. That is then divided by 20 to give you the result that you see.

If you want the correct result, then you need to do:

System.out.println("Strange " + (20 * 232792560L) / 20);

(Marking a literal with an L means that the constant maths will be done with long, rather than with int, so this will no longer overflow.)