Confused??

[Joe San]

Hi Ranchers,

why it prints 3 here. I thought is shuould be 1,

int i = 0;
 int j = 0;
 boolean t = true;
 boolean r;
 r = (t & 0<(i+=1));
 r = (t && 0<(i+=2));
 System.out.println(i); // 1 should be printed??

Thanks in advance.

[Taihua Yu]

well,guys
First,I think you confused && with ||
if you use ||,the first statement is right,the second is not executed,but,to &&,the result is not that!
best wishes!



yours
Taihua

[Sanjeev Singh]

Jothi,
I think you have got the answer.Dig more deeper by changing & with | and && with ||.

[Joe San]

Hi Sanjeev,

I actually know this long before and sometimes I get dugged with these kind of simple questions. I dont know what to do...Anyways thaks for helping this out for me.

[Joe San]

Hi Sanjeev,

I actually know this long before and sometimes I get dugged with these kind of simple questions. I dont know what to do...Anyways thaks for helping this out for me. So the point is with the && opertor, if the first operand eveluates to true, it checks for the other operand as well and that should be true in order for the condition to be true. To the contrary, if the first operand evaluates to false, then && wont check for the second operand and the result of the entire expression is false.

[Saurabh Vyas]

so Jothi I guess now you understood why the answer is 3

[Sanjeev Singh]

Jothi,
I think you have got the key difference between the two operators anyway try this

1. class TestOR {
2. public static void main(String[] args) {
3. if ((isItSmall(3)) || (isItSmall(7))) {
4. System.out.println("Result is true");
5. }
6. if ((isItSmall(6)) || (isItSmall(9))) {
7. System.out.println("Result is true");
8. }
9. }
10.
11. public static boolean isItSmall(int i) {
12. if (i < 5) {
13. System.out.println("i < 5");
14. return true;
15. } else {
16. System.out.println("i >= 5");
17. return false;
18. }
19. }
20. }

This is a K&B book problem ,revisit it!

[Joe San]

Yes Sanjeev,

I got it now. Sometimes, I tend to forget them. Anyways thanks all ranchers for the help.

[Burkhard Hassel]

Short circuits, && and ||

A && B
(A AND B) can short circuit only if A is false. Then the whole expression will be false, B has not to be tested.
If A is true, B has to be tested as well, cause if B is false, the whole expresion would still be false.


A || B
(A OR B) can short circuit only if A is true. Because regardless of B the whole expression would be true.


A ^^ B does not exist
A short circuit of A XOR B cannot work...


A&B or A|B are without short circuit, both A and B are tested in any case.




Yours,
Bu.