Integer.numberOfLeadingZeros() Method in Java With Example

The Integer.numberOfLeadingZeros(int value) method returns the number of zero bits before the first (leftmost) 1-bit in the binary representation of the given integer. If the value is 0 (i.e., no 1-bits), it returns 32.

Syntax :

public static int numberOfLeadingZeros(int arg)

Parameter: This method accepts a single parameter arg, which is the integer value.

Return Value: This method returns the number of zero bits preceding the highest-order set-bit in the two's complement binary representation of the specified int value or 32 if the value is equal to zero.

Program 1: Below programs illustrate the java.lang.Integer.numberOfLeadingZeros() method. with positive number.

java

public class LeadingZeros {

    public static void main(String[] args) {

        int a = 19;
        System.out.println("Integral Number = " + a);

        // Returns the number of zero bits preceding the highest-order one-bit
        System.out.print("Number of Leading Zeros = ");
        System.out.println(Integer.numberOfLeadingZeros(a));
    }
}

Output

Integral Number = 19
Number of Leading Zeros = 27

Explanation:

Consider any integer arg, like int arg = 19;
Binary Representation(32-bit) of 19 = 00000000 00000000 00000000 00010011
First (leftmost) 1 bit is at position 27 (index starts from 0).
number of leading zeros = 32 - 5 = 27

Program 2: For a negative number.

java

public class LeadingZeros {

    public static void main(String[] args) {

        int a = -15;
        System.out.println("Number = " + a);

        // Returns the number of zero bits preceding the highest-order one-bit
        System.out.print("Number of Leading Zeros = ");
        System.out.println(Integer.numberOfLeadingZeros(a));
    }
}

Output

Number = -15
Number of Leading Zeros = 0

Program 3: For a decimal value.

java

public class LeadingZeros {

    public static void main(String[] args) {

        // Cast double to int explicitly
        System.out.print("Number of Leading Zeros = ");
        System.out.println(Integer.numberOfLeadingZeros((int) 16.32)); 
    }
}

Output

Number of Leading Zeros = 27

Note:It returns an error message when a decimal value is passed as an argument.

Program 4: For a string value is passed in argument.

java

public class LeadingZeros {

    public static void main(String[] args) {

        // Convert String to int
        int number = Integer.parseInt("18");

        // Returns the number of zero bits preceding the highest-order one-bit
        System.out.print("Number of Leading Zeros = ");
        System.out.println(Integer.numberOfLeadingZeros(number));
    }
}

Output

Number of Leading Zeros = 27

Note:It returns an error message when a string is passed as an argument.

Integer.numberOfLeadingZeros() Method in Java With Example

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