Java Operators with Numbers

Question

How it works the & Operator with numbers? For example:

x = 8 & 4;

and the answer is 0.

How can i find the answer without using java or any other program?

And http://docs.oracle.com/javase/tutorial/java/nutsandbolts/op3.html — Jon Skeet, Mar 01 '14 at 14:38
possible duplicate of [Difference between & and &&](http://stackoverflow.com/questions/5564410/difference-between-and) — timrau, Mar 01 '14 at 14:41
@timrau No, not even close.. This is bitwise math and the "duplicate" talks about how `&&` short-circuits while `&` doesn't. — Josh M, Mar 01 '14 at 17:04

score 3 · Answer 1 · answered Mar 01 '14 at 14:39

Java has three kinds of "AND" operators - the logical one, which is &&, a bitwise one, which is &, and a & on booleans, which does not short-circuit. Java compiler can distinguish between the kinds of operators by examining the type of the operands.

Bitwise operator takes binary representations of its operand, performs "AND" on each bit, and returns the result as a number.

For 4 and 8, bitwise "and" is zero, because they do not have 1 bits in common:

    00000100 -- 8
    00001000 -- 4
    --------
  & 00000000 -- 0

For other numbers, say, 22 and 5, the result would be different:

    00010110 -- 22
    00000101 --  5
    --------
  & 00000100 --  4

score 3 · Accepted Answer · answered Mar 01 '14 at 14:41

3

You can find the answer without using Java converting the numbers into binary format:

4 = 0100
8 = 1000

If you perform an AND operation on each bit, you get:

0 & 1 = 0
1 & 0 = 0
0 & 0 = 0
0 & 0 = 0

That's why it's zero.

answered Mar 01 '14 at 14:41

helderdarocha

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score 1 · Answer 3 · answered Mar 01 '14 at 14:40

1

& is a bitwise and operator ... the binary values of 8 and 4 are

8 = 1000
4 = 0100

if you know how AND operator works then you know that

1 & 0 = 0;

so after a bitwise AND, there will be all 0

answered Mar 01 '14 at 14:40

stinepike

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Java Operators with Numbers

3 Answers3