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Doubt

AJAY JOSE PAUL
Greenhorn

Joined: Nov 11, 2006
Posts: 4
The following code will print 'false'.

float f = 1.0F/3.0F;
System.out.println( (f * 3.0F) == 1.0F );

Answer : A True
Answer : B False

Your comments please... with explanations.


M sorry... I must admit I have not read the faq / forum rules... So lemme know if m violating any.


I am not a player, I am the 'GAME'
Manjunath Hirennavar
Greenhorn

Joined: Nov 15, 2006
Posts: 24
Hi AJAY,
Execute this code it will print definitely true.
why because everywhere we are using the float variable...............!

Thanks and Regards
Manjunath
Barry Gaunt
Ranch Hand

Joined: Aug 03, 2002
Posts: 7729
You topic title: "Doubt" seems to imply you have a question? What exactly is your question? On my system with Java 5.0 the program prints "true".


Ask a Meaningful Question and HowToAskQuestionsOnJavaRanch
Getting someone to think and try something out is much more useful than just telling them the answer.
Sanjeev Singh
Ranch Hand

Joined: Nov 01, 2006
Posts: 381
Though it is printing true but I am surprised with the answer.In my opinion it should be false because dividing 1.0f/3.0f will give a resulting float with somevalue like .33333...
Again multiplying this number by 3 will not print 1..(will be slightly less than one).


~Sanjeev Singh<br />SCJP 1.5
Manjunath Hirennavar
Greenhorn

Joined: Nov 15, 2006
Posts: 24
Hi Sanjeev,

First I apologize for the explaination.....answer is correct but explaination is not satisfiable...I'm apologize all for that.

Mathematically you are right........Sanjeev,
but if you print(f*3.0F) its printing 1.0 why because
as of Java 5 our JVM is considering 0.99999999 as 1.0
so when we devide 1.0 by 3.0 it will be 0.33333333.....
when again we multiply this factor by 3.0 then the answer is 0.99999999...
Mathematically we can't prdict the no.of 9's but our JVM is having limitation of memory. Thats why its considering it 1.0 and printing true.......!

This is how I think about it...any other views about it..
always welcome....!

Thanks and Regards
Manjunath
AJAY JOSE PAUL
Greenhorn

Joined: Nov 11, 2006
Posts: 4
You topic title: "Doubt" seems to imply you have a question? What exactly is your question? On my system with Java 5.0 the program prints "true".


@Barry Gaunt ::: I compiled and ran the proggy... it prints true.

According to me the output should b false.

I wanted to know the reason for printing true as the output.
Sanjeev Singh
Ranch Hand

Joined: Nov 01, 2006
Posts: 381
Posted by Manjunath
as of Java 5 our JVM is considering 0.99999999 as 1.0


Compiling and running code with jdk 1.4 is also giving the answer as true.
 
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subject: Doubt