What does the ">>" symbol mean in Java? [duplicate]

Question

I see a line in some code I'm looking at and it says (12 >> 1) - 1). I print that value out and it comes out as a 5. If I change the 12 to 5, it comes out as a 1.

What is the ">>" symbol doing exactly?

Answer 1

>> is the signed right shift operator. It shifts a bit pattern to the right. The bit pattern is given by the left-hand operand, and the number of positions to shift by the right-hand operand.

When you shift right two bits, you drop the two least significant bits.

Let’s say, x = 00111011

So when you do, x >> 2, it results in x = 00001110

This is essentially the same thing as dividing a value by 4 or by 2 two times while dropping the fractional part.

So, below code will result in 4:

byte val = 100; val = (byte) (val >> 2); System.out.println(val); 

Explaining your example:

• The binary representation of 12 is: 1100
• 12 >> 1 is equivalent to 0110 which is 6 in decimal
• so (12 >> 1) - 1) is equivalent to 6-1 that is 5

Answer 2

12 is 1100 in binary. A right shift (>> is the bitwise right shift operator) by one bit produces

1100 -> 0110  

which comes out to be 6.

Thus we have that,

6 - 1 = 5