What is JavaScript >>> Operator and How to use it ?

Last Updated : 19 Feb, 2020

The JavaScript >>> represents zero-fill right shift operator. It is also called the unsigned right bit shift operator. It comes under the category of Bitwise operators. Bitwise operators treat operands as 32-bit integer numbers and operate on their binary representation.

Zero-fill right shift (>>>) operator:
It is a binary operator, where the first operand specifies the number and the second operand specifies the number of bits to shift. The operator shifts the bits of the first operand by a number of bits specified by the second operand. The bits are shifted to the right and those excess bits are discarded, while 0 bit is added from left. As the sign bit becomes 0, the operator ( >>> ) returns a 32-bit non-negative integer.

Example:

Input:
A = 6 ( 00000000000000000000000000000110 )
B = 1 ( 00000000000000000000000000000001 )

Output:
A >>> B = 3 ( 00000000000000000000000000000011 )

Syntax:

result = expression1 >>> expression2

Difference between >>> and >> :
The difference between these two is that the unsigned zero-fill right shift operator (>>>) fills with zeroes from the left, and the signed right bit shift operator (>>) fills with the sign bit from the left, thus it maintains the sign of the integer value when shifted.

Example: This example implements the use of >>> operator:

Program:

<!DOCTYPE html>
<html>
  
<head>
    <title>>>> Operator in JavaScript</title>
      
    <style>
        body {
            text-align: center;
        }
          
        h1 {
            color: green;
        }
    </style>
</head>
  
<body>
    <h1>GeeksforGeeks</h1>
    <h3>The >>> Operator in JavaScript</h3>
      
    <script>
        document.write("For non negative number:<br>");
        var a = 12;
  
        // Shift right two bits
        var b = 2;
        document.write("a = " + a + " , b = " + b);
        document.write("<br>a >>> b = " + (a >>> b) + '<br>');
  
        document.write("<br>For negative number:<br>");
        var a = -10;
      
        // Shift right two bits
        var b = 3; 
        document.write("a = " + a + " , b = " + b);
        document.write("<br>a >>> b = " + (a >>> b) + '<br>');
    </script>
</body>
  
</html>

Output:

Explanation: For non-negative numbers, zero-fill right shift (>>>) and sign-propagating right shift (>>) gives the same output. For example, 9 >>> 2 and 9 >> 2 gives same result i.e. 2. But for negative numbers, -9 >>> 2 gives 1073741821 and -9 >> 2 gives -3 as output.

Case 1: non-negative number
    12 (base 10): 00000000000000000000000000001100 (base 2)
                   --------------------------------
    12 >>> 2 (base 10): 00000000000000000000000000000011 (base 2)
    = 3 (base 10)

Case 2: negative number
    -10 (base 10): 11111111111111111111111111110110 (base 2)
                    --------------------------------
    -10 >>> 3 (base 10): 00011111111111111111111111111110 (base 2)
    = 536870910 (base 10)

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