Found this Java interview question on another site, but it doesn't give the answer.
public class test {
public static void main(String[] args)
{
int i=5;
i=i++;
System.out.println("result::"+i);
}
}
I would guess it print 6 but i'm not too sure.
FFS it would take you a fraction of the time it took to post this, just to compile and run it!
You're right i should have tested it first, but i was hoping for an explanation not just the answer, and i knew many here would know the answer without testing it.
There was user comments on the website and most of them thought the answer was 5 , so i was kinda assuming i was wrong about it being 6.
I just tested it and got 5. I thought the prefix increment happened AFTER the line: "i=i++;" was executed, therefore "System.out.println("result::"+i);" would print 6.
1. It's postfix not prefix, this is prefix++i
2. The postfix operator is applied after the evaluation of the expressioni++; // result of expression is value of i before increment
3. So i gets assigned the value of evaluating the expression i++, meaning that i gets assigned the value of i before the increment.
It's basically like thisi = 5
temp = evaluate the expression i++ // temp is now 5
increment i // i is now 6
i = temp // i is now 5
int i=0;
System.out.println(i++ +" "+i+" "+ ++i +" "+ i-- +" "+ --i);
If you can make a good guess before you compile, You got them better!
:-)
Hey guys,
just try that example with a C-compiler. The result will be 6, so maybe there is something wrong in the Java world ?
> Hey guys,
>
> just try that example with a C-compiler. The result
> will be 6, so maybe there is something wrong in the
> Java world ?
Why would you say that? If you expect Java to do everything exactly the same as C then why would we need it?
Anyway, the result of this code is most likely undefined in C; however, it is well defined in Java. Either way, this type of coding is considered a VeryBadThing(TM).
> so maybe there is something wrong in the
> Java world ?
No, nothing wrong in the Java world
The behaviour of this idiotic construct was never defined for C, so you get whatever the specific compiler gives you.
The Java behaviour, on the other hand, is clearly defined, and you consistently get the expected result.
Guys you are right.
BTW: look at http://skeletoncoder.blogspot.com/2006/09/java-tutorials-i-i.html
> Guys you are right.
Yeah, we know. ;o)
It's not the first (or seemingly thousandth) time this has been discussed around here. Notice the similarity between the blog post you mention (September, 2006) and the explanations given previous to that post:
http://forum.java.sun.com/thread.jspa?threadID=725106&messageID=4179124
http://forum.java.sun.com/thread.jspa?threadID=755675&messageID=4320434
http://forum.java.sun.com/thread.jspa?threadID=770353&messageID=4389965
~
> Hey guys,
>
> just try that example with a C-compiler.
Not necessarily. In C, it's undefined, so some might be 5 and some might be 6.
> The result
> will be 6, so maybe there is something wrong in the
> Java world ?
That makes no sense. You're saying C is always "correct" and anything in Java that's different is "wrong"?
Java is behaving exactly as it's defined to, as explained above. C doesn't define what happens here.
> 1. It's postfix not prefix, this is
> prefix
post-increment/pre-increment.
