Bitwise Right Shift Operators in Java

In C/C++ there is only one right shift operator ‘>>’ which should be used only for positive integers or unsigned integers. Use of the right shift operator for negative numbers is not recommended in C/C++, and when used for negative numbers, the output is compiler dependent. Unlike C++, Java supports following two right shift operators.

Here we will be discussing both of right shift operators as listed:

• Signed right shift “>>”
• Unsigned right shift “>>>”

Type 1: Signed Right Shift    

In Java, the operator ‘>>’ is signed right shift operator. All integers are signed in Java, and it is fine to use >> for negative numbers. The operator ‘>>’ uses the sign bit (leftmost bit) to fill the trailing positions after the shift. If the number is negative, then 1 is used as a filler and if the number is positive, then 0 is used as a filler. For example, if the binary representation of a number is 10….100, then right shifting it by 2 using >> will make it 11…….1.

Example:

Java

// Java Program to Illustrate Signed Right Shift Operator

// Main class
class GFG {

    // Main driver method
    public static void main(String args[])
    {

        int x = -4;
        System.out.println(x >> 1);

        int y = 4;
        System.out.println(y >> 1);
    }
}

Output

-2
2

Type 2: Unsigned Right Shift Operator 

In Java, the operator ‘>>>’ denotes unsigned right shift operator and always fill 0 irrespective of the sign of the number.

Example:

Java

// Java Program to Illustrate Unsigned Right Shift Operator

// Main class
class GFG {

    // main driver method
    public static void main(String args[])
    {

        // x is stored using 32 bit 2's complement form.
        // Binary representation of -1 is all 1s (111..1)
        int x = -1;

        // The value of 'x>>>29' is 00...0111
        System.out.println(x >>> 29);

        // The value of 'x>>>30' is 00...0011
        System.out.println(x >>> 30);

        // The value of 'x>>>31' is 00...0001
        System.out.println(x >>> 31);
    }
}

Output

7
3
1

Time Complexity: O(1).

Space Complexity: O(1) as no extra space has been used.

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