Perl - left shift operator

The Bitwise left shift operator (<<) takes the two numbers and left shift the bits of first operand by number of place specified by second operand. For example: for left shifting the bits of x by y places, the expression (x<<y) can be used. It is equivalent to multiplying x by 2y.

The example below describes how left shift operator works:

1000 << 2 returns 4000

(In Binary)
1000         ->    1111101000
<< 2                     |  left shift the bits
-----                    V  by 2 places
4000         <-  111110100000
(In Binary)

The code of using left shift operator (<<) is given below:

\$x = 1000;

#left shift operation
\$z = \$x << 2;

#Displaying the result
print("z = \$z");

The output of the above code will be:

z = 4000

Example: Count number of 1 Bits in a positive integer

Consider an integer 1000. In the bit-wise format, it can be written as 1111101000. However, all bits are not written here. A complete representation will be 32 bit representation as given below:

00000000000000000000001111101000

Bitwise AND operation with 1 at any bit results into 1 if the bit is 1 or 0 if the bit is 0. Performing such operation at every bit, and counting the number of 1 gives the count of 1 bits in the given positive integer. To achieve this bitwise left shift operator can be used as shown in the example below:

sub CountOneBits {
#passing argument
\$n = \$_;

\$count = 0;

#performing bitwise AND operation
#at every bit of the number
for (\$i = 0; \$i < 32; \$i++) {
\$count++;
}
}

return \$count;
}

print("CountOneBits(1000) = ".CountOneBits(1000)."\n");
print("CountOneBits(1023) = ".CountOneBits(1023)."\n");

The above code will give the following output:

CountOneBits(1000) = 6
CountOneBits(1023) = 10

❮ Perl - Operators

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