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Question: What is difference between & and && in java

Answer: Single Ampercent (& ) can be used as Bitwise operator and Boolean logical operator.

Now the difference arises when & is used as logical operator.

This can be best explained with the help of an example.

int i=5;
if(i<3 & i++ < 10)
{
//perform action
}

Now in this case
First expression is i<3
Second expression is i++ < 10

when & is used it will evaluate both the expressions regardless of the fact that it finds first expression as FALSE and only then will it give an answer.

Whereas if && was used in place of & , after it had evaluated first expression and had found result of first expression as FALSE, it would not have evaluated second expression. Thus saving time.

FYI... && is also called as counterpart of & and the evaluation it does is called short-circuit evaluation.



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Question: What is difference between & and && in java


Answer:

Single Ampercent (& ) can be used as Bitwise operator and Boolean logical operator.

Now the difference arises when & is used as logical operator.

This can be best explained with the help of an example.

int i=5;
if(i<3 & i++ < 10)
{
//perform action
}

Now in this case
First expression is i<3
Second expression is i++ < 10

when & is used it will evaluate both the expressions regardless of the fact that it finds first expression as FALSE and only then will it give an answer.

Whereas if && was used in place of & , after it had evaluated first expression and had found result of first expression as FALSE, it would not have evaluated second expression. Thus saving time.

FYI... && is also called as counterpart of & and the evaluation it does is called short-circuit evaluation.

Source: CoolInterview.com


I don't agree that the single '&' evaluates both the conditions regardless of the result boolean value.

int i=5;

if(i<1&i!=-1)
{
System.out.println("NOT EVALUATED");
}

Here the value is not printed.
Source: CoolInterview.com

Answered by: Amit Rane | Date: 9/4/2007 5:23:59 PM | Contact Amit Rane Contact Amit Rane

For the above example the print statement won't work as the condition is not true.
this doesn't mean that it is not evaluating the second condition.

If u try an example as below
int i=0;
if(i<1 && i++!=5)
{
System.out.println("not evalutaed");
}
System.out.println(i);

u will get i value as 5 only. But if u r trying with single & ,then the i value will be 6.

This shows that single & will evaluate both the expressions regardless of the fact that it finds first expression as FALSE and only then will it give an answer.


Source: CoolInterview.com

Answered by: meenu | Date: 3/30/2010 | Contact meenu Contact meenu

& is bitwise and operator whereas && is short circuit operator.
when we are using & both the side left and right side operand would be evaluated. In some case only evaluation of left side could decide the result.In that case we use short circuit operator.its a new addition Source: CoolInterview.com

Answered by: vibha | Date: 6/4/2010 | Contact vibha Contact vibha


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