For Loop

Consider the code below
int i=0,j=0;
while(i+j<20)
{
System.out.println(i+j);
j+=i;
}
This loop executes JUST ONCE(??) when it should be an infinite loop.There is an abrupt completion of the loop.I think the problem is in the j+=i; statement 'cause removing it results in an infinite loop.BUT WHAT IS THE PROBLEM??

Anybody please help me here.I am giving the exam next week.
I request the moderators of this forum to help me out on this one.
Thank you.

Hi Udayan
I tried your code and its an infinite loop as expected. So I am sorry to say, I didn't get your doubt

If you can explain the situation more clearly it will be helpful.
Thanks
ARS Kumar.

Udayan,
In my case the code behaves in the same wierd way as yours.That is it only prints 0 once and terminates, but if you remove the statement j+=i, the loop executes infinately.This is a strange behaviour indeed and following the logic of the loop I do not yet see why the loop should execute just once.But since ARS Kumar says on his machine it behaves normally, then I dont see whether we need to compare Systems we are using, if it is anything to do that. Let us woo more people to try the code and see if we can have a general behaviour. I will come back when I figure out something.
Regards,
Herbert

Hi All
I tried the code on my machine and it goes into an infinite loop,i am using
java version "1.2.2"
Classic VM (build JDK-1.2.2-W, native threads, symcjit)
On Windows NT.

Hi Friends
I am using JDK 1.2.2 on a Win98 PC. I am very curious to see the result of this !
Thanks
ARS Kumar

Hi all,
I just execute the code above, it execute once, it is not infinite loop. I am confused the result too.

Hi ppl
i m getting abnormal behaviour of the program. as it prints O (ZERO) for one time only and then exit the loop
i m using JDK1.2

hai ,
i run the program in jdk1.3 win98 and got strange result
infinite loop with 0(zero).
thanks
shiva

HAI
i forget to mention the condition that
it ran in to loop woth or without j+=i statement.
thanks
shiva

OF COURSE its an infite loop; with or without j=i+j.
Check OS to figure out if it has restriction on infinite loops:-)

Hi,
Same with me..executed once with o/p 0 , then terminated..
jdk 1.2 on WinNT

Hi all,
I used different jdk compiler to try this code, 1.3 is infinite
and 1.2 is no. I discuss this issue with someone. I think this is
virture machine bug. so it is better to report to sun.

Thanks all for ur replies.The loop really had me in a tizzy.I will be sure to report this to Sun.I will also quiz some Java experts and get back to all of u with the answer.
Thanks all

Udayan:
I am on Win '98 running java version given below:
java version "1.2.2"
Classic VM (build JDK-1.2.2-001, native threads, symcjit)
This gives me an infinite loop......
So I don't think I see a prob.
Regds.

- satya

Dear All,
I tried with this code.I got same as Udayan was getting ,Like it is executing once and if you remove j+ = i statement it is in infinite loop;
I am using JDK 1.2 and Win NT.
Thanks
Netla
[This message has been edited by Netla Reddy (edited June 18, 2000).]

Hi Udyan,
With the code you have given,I got 0 printed and when I removed the statement j+=i, it is an infinite loop.
I am using Windows95 and
java version "1.2.1"
Classic VM (build JDK-1.2.1-A, native threads)
Suma

I am using Sun jdk on Win98
java version "1.2.1"
Classic VM (build JDK-1.2.1-A, native threads)
I still cannot understand it.I have quizzed some java experts on this.Still awaiting the answer.Will get back on this topic asap.

Hi Udyan & All

,
I too tried that on Windows98.It's an infinite loop.
I am using :
java version "1.2.2"
Classic VM (build JDK-1.2.2-W, native threads, symcjit)
its very interesting

!
regards..

Hi all,
I too executed this in JBuilder 2.o ,I got the infinite of '0'.
I am also curious to know the resulit.
Thanks.
/nirmal

I am using windows 98 and jdk1.2.1
it goes into an infinite loop

Runs in infinite loop with or without condition j+=i; I tested it on WindowsNT4 Client and jdk1.2

I tried my code on my Linuxppc (iMac) JDK1.2, it is normal. I also tried on an Enterprise SUN OS 5 (JDK1.2) and I don't see any problem. 20 is a much larger number compared to 0. If there is a problem, I think SUN deliberately makes trouble for Microsoft.

Hai,
I ran the program using visual cafe 3 and got
an infinite loop printing zero .

Runs in an Infinite Loop with or without j+=i.I am running Java 1.2.2 on Windows NT platfrom.

On an SGI(UNIX), with
java version "1.2"
Classic VM (build JDK-1.2-V, green threads, mipsjit)
I go into an infinite loop, printing 0.
Regds.

- satya

Hi
I tried your code. It gave 0. Jdk version is 1.2.1 on Windows NT4.0. If the j+=i is removed it is going into an infinite loop printing 0 infinite times.

hi all,
this code printed 0 infinte times omn my m/c. i'm using jdk1.3 on winNT 4.0

It goes into infinite loop with 0 output, with or without j+=i;
I'm running java version "1.2.2"
Classic VM (build JDK-1.2.2-005) on Win NT 4 Client
on PIII 600 MHz.

[This message has been edited by Harry Chawla (edited July 26, 2000).]

Hi all,
I executed this in JBuilder 3.0 ,I got the infinite of '0'with the statement or without the statement j+=i;
I am also curious to know the result.
Babu

Hi! everybody,
I ran the following code in Win98 with jdk1.2.2
public class Forloop {
public static void main(String[] args){
int i=0,j=0;
for(; i+j < 20

{
System.out.println(i+j);
j += i;
}
}
}
and got strange result, only once it executed with 0 output.
Can anybody explain why? it should have been an infinite loop isn't it?
Anil

Hey Guys,
For all those of you who got a '0' instead of an infinite loop, when you ran it, you are in for another surprise.
As somebody pointed out, the problem does not seem to be in the j+=i; statement. Rather the problem seems to be the type of the variable.
Okay change the original code to look like this.
(I have just changed the type of the variable to float instead of int) and everybody should now start getting infinite loops.
float i=0,j=0;
while(i+j<20)
{
System.out.println(i+j);
j+=i;
}
Intriguing stuff huh ?
Best Regards

For the people who are NOT getting an infinite loop, would you please run it through the debugger and see what values the variables are taking through each iterations.
Thanks!

Hi! all,
I ran the code in two different platforms, LINUX and WIN98,
Linux:
Kaffe Virtual Machine
Engine:Just-in-time ver:1.0b4 java ver: 1.1
and Win98:
Java Version: 1.2.1
Native Threads:1.2.1-A
and got strange results. In Linux its giving infinite loop with output 0 and with Win98 its giving only 1 output with 0.

Hi
Can some body from the ranch please try to get his hands on this one.
I remeber one such kind of post where a ranch hand was able to figure out that different resultsets on different system were as a result of differnce in speed of PC processor.
Thanks.

hi, guys
i have execute the code too, it print 0, and infinite loop,
java version "1.2.2"
Classic VM (build JDK-1.2.2_005, native threads, symcjit)
running windows2000 professional
i have looked locals in debugger, there is nothing unusual.
so what about your debugger info?

Hi Udayan,
As per the code....the loop should only run once as there is no condition for the loop to restart(-ie-no increments) and hence after executing once it will exit out if no statements after that.

Originally posted by Udayan:
Consider the code below
int i=0,j=0;
while(i+j<20)
{
System.out.println(i+j);
j+=i;
}
This loop executes JUST ONCE(??) when it should be an infinite loop.There is an abrupt completion of the loop.I think the problem is in the j+=i; statement 'cause removing it results in an infinite loop.BUT WHAT IS THE PROBLEM??

Chamya,
A loop is not required to have an increment statement.
The following code is valid and results in an infinite loop:
w=5
while (w>0)
{ System.out.println(w);
}
THe issue being discussed here is a problem with certain implementations of java not handling infinite loops correctly.