short circuit evaluations

[JS#]

Hi all, does anyone have any code that will prove java uses short circuit
evaluation e.g. (expr1 && expr2), if expr1 is false it will stop evaluating.
Thanks in advance
JS

 

[VisionSet]

Hi all, does anyone have any code that will prove java uses short circuit
evaluation e.g. (expr1 && expr2), if expr1 is false it will stop evaluating.
Thanks in advance

public static void main(String[] args) throws DAOException {

int x = 1, y = 2;
boolean b, c;
b = true;
c = false;

if ((b = (x == 0)) && (c= (y == 2))) ;

System.out.println("b should be false: b= " + b);
System.out.println("c should be false: c= " + c);

b = true;
c = false;

if ((b = (x == 0)) & (c= (y == 2))) ;

System.out.println("b should be false: b= " + b);
System.out.println("c should be true: c= " + c);
}

 

[Jimi Hullegård]

Hi all, does anyone have any code that will prove java uses short circuit
evaluation e.g. (expr1 && expr2), if expr1 is false it will stop
evaluating.
Thanks in advance

public class NullTest
{
public static void main(String args[])
{
String a = "a";
String b = null;
if (a.equals("b") && b.equals("a"))
{
System.out.println("a == b??? and what about
NullPointerException??");
}
System.out.println("a != b ");
}
}

If java whould evaluate both expressions in the if-statement, then it would
make a call to the equals-method of object b. But since b is null that would
cause an NullPointerException. If you run this program, you will see that no
exception is thrown. If you then change the a string to be "b" instead of
"a", then the first expression evaluates to true, and java evaluates the
second expression, resulting in a NullPointerException.

/Jimi

 

[Roedy Green]

Hi all, does anyone have any code that will prove java uses short circuit
evaluation e.g. (expr1 && expr2), if expr1 is false it will stop evaluating.
Thanks in advance
JS

see http://mindprod.com/jgloss/multiposting.html

 

[JS]

Thanks for your help everyone. I was thinking way too deeply about it,
posted here then came up with the answer. Cheers

Roedy said:

see http://mindprod.com/jgloss/multiposting.html

Yes I know, but I wasnt sure which group would respond. I dont normally
multipost but just this once.
sorry

 

[Roedy Green]

Yes I know, but I wasnt sure which group would respond. I dont normally
multipost but just this once.

even when you want to post to multiple groups, cross-post, don't
multi-post. See http://mindprod.com/jgloss/crossposting.html