Question from Khalid's Book

[Roopa Bagur]

This is a question from Khalid A.Mughal's book. I thought I knew the answer right but the right answer has left me confused
public class logic
{
public static void main(String[] args)
{
int i=0;
int j=0;
boolean t=true;
boolean r;
r=(t& 0<(i+=1));
r=(t&& 0<(i+=2));
r=(t |0<(j+=1));
r=(t | |0<(j+=2));

System.out.println(i +""+j);
}
}
What is the output.
The answer according to the book is 3 and 1.
I thought it would be 1 & 1. Can anybody explain this to me.

[Ragu Sivaraman]

I got the i part . i is 3
i is changed two different places so it will be 3
But i am sure how the answer for j is 1?
Some one have any idea?

[Anonymous]

I think I've got a fair measure of what this problem is about.
The operator | |, as we know, is a short circuit operator. It means that if the result of the operation can be determined by the left hand operand alone, then the right hand operand will be omitted.
In the case of the | | operator, the truth table is :

• True | | True = True
  
• True | | False = True
  
• False | | True = True
  
• False | | False = False
  

In our case, the left hand operand of the fourth expression r=(t | | 0<(j+=2)); evaluates to a "True". Since "True" with any combination of True or False returns True for the | | operator, the system decides not to waste its resources in evaluating the Right Hand portion of the operator and just returns True. Consequently, the expression (0<(j+=2)) does not get evaluated and therefore the final value of j is 1.
Hope this helps
Shyam
[This message has been edited by Shyamsundar Gururaj (edited September 09, 2001).]