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Short-Circuit Evaluation

 
Satyajeet Kadam
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As per K&M book , Short circuit operators are applied to boolean opernads.

Follwing link is shwows an example where && operator is applied on integer operands?

This example is

from:http://java.sun.com/docs/books/tutorial/java/nutsandbolts/op2.html


class ConditionalDemo1 {
public static void main(String[] args){
int value1 = 1;
int value2 = 2;
if((value1 == 1) && (value2 == 2)) System.out.println("value1 is 1 AND value2 is 2");
if((value1 == 1) || (value2 == 1)) System.out.println("value1 is 1 OR value2 is 1");

}
}

Q1)Why this operator is applied on integer operands?
Q2)Can you tell me working of &,&&,|,|| and also the difference in
each of them? with code?
Q3) Is there any trick to remmber this stuuf
 
Jeremy Botha
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Hi.

In the example you've pased, the && and || operators are applying to boolean expressions.

== is the equality operator; it evaluates the left and right hand operands, returning true if they are equal or false otherwise.

So, the expressions you have listed reduce as follows:

and


with regards to Q2:

& and | are bitwise operators, whereas && and || are boolean operators.

& and | apply at the bit level of the operands; that means that they evaluate every bit of the lhs operand against the corresponding bit in the rhs operand:


will print out


You can easilly check the above results by writing out the binary representation of 3 and 7, then doing bitwise anding and oring between the digits.

Q3: Not really, it's just something you should know.

Jeremy
 
Ernest Friedman-Hill
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"&" and "|" can actually also be applied to boolean arguments, in which case they are equivalent to "&&" and "||" except that they don't do short-circuit evaluation: they always evaluate both arguments.
 
Jeremy Botha
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True.

Jeremy
 
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