Possible Duplicate:
>> in javascript
I'm going through some code and I ran into 2 weird operators: >> and <<,
in the form of 2<<3 and 442132132>>546542132.
I deduced that x<<y means x times 2 in the power of y. Meaning, 4<<3 is 4*(Math.pow(2,3)), which is 32, but I couldn't find what x>>y means.
I know it usually returns 0 for small numbers, but when high numbers are involved, the result is usually a small number.
From Mozilla:
Left shift a << b Shifts a in binary representation b (< 32) bits to the left, shifting in zeros from the right.
Sign-propagating right shift a >> b Shifts a in binary representation b (< 32) bits to the right, discarding bits shifted off.
442132132>>546542132 seems excessive for a number that is only 32 bits wide.
The >> operator bit-shifts the left value by the right one.
a >> b is equivalent to parseInt(a / Math.pow(2, b)).
For example:
1 >> 0 == 1
4 >> 1 == 2
6 >> 1 == 3
42 >> 3 == 5
0x120 >> 4 == 0x12
0x129 >> 4 == 0x12
0x12f >> 4 == 0x12
0x130 >> 4 == 0x13
<< is the bitwise left operator, and >> is the bitwise right operator.
These shift the value on one side of the equation by the value on the other.
It's converted into binary, and then moved to the left or the right. Like 2 << 3:
0000010
becomes:
0010000
Or 16 if you convert it back.
>> is the other way round: (16 >> 3) === 2.
These are the binary shift operators. A
As you know, numbers are represented in binary in computers (6 = 110 , 9 = 1001, etc.)
A left bit shift "<<" shifts the binary digits to the left. For instance, 6 << 2 shifts 6 (i.e. 110) two binary digits.
Also note that in a 32-bit environment, 32-bits would be used to represent an integer, so 6 would be:
0000 0000 0000 0000 0000 0000 0000 0110
6 << 2 (6 shifted 2 to the left):
0000 0000 0000 0000 0000 0000 0001 1000
6 >> 2 (6 shifted 2 to the right):
0000 0000 0000 0000 0000 0000 0000 0001
