Java lang.Long.numberOfTrailingZeros() method in Java with Examples

java.lang.Long.numberOfTrailingZeros() is a built-in function in Java which returns the number of trailing zero bits to the right of the lowest order set bit. In simple terms, it returns the (position-1) where position refers to the first set bit from the right. If the number does not contain any set bit(in other words, if the number is zero), it returns 64.

Syntax:

public static long numberOfTrailingZeros(long num)
Parameters:
num - the number passed 
Returns:
the number of trailing zeros after the lowest-order set bit

Examples:

Input :  8
Output : 3 
Explanation: Binary representation of 8 is 1000 
No of trailing zeros to the right of the lowest-order set
bit is 3. 

Input : 191
Output : 0 

The program below illustrates the java.lang.Long.numberOfTrailingZeros() function:

Program 1:

// Java program that demonstrates the
// Long.numberOfTrailingZeros() function

// include lang package
import java.lang.*;

public class GFG {

    public static void main(String[] args)
    {

        long l = 8;

        // returns the number of zero bits following the lowest-order
        // set bit
        System.out.println("Number of trailing zeros = "
                           + Long.numberOfTrailingZeros(l));

        // second example
        l = 25;
        System.out.println("Number of trailing zeros = "
                           + Long.numberOfTrailingZeros(l));
    }
}

Output:

Number of trailing zeros = 3
Number of trailing zeros = 0

Program 2: The program below demonstrates the use of function when a negative number is passed.

// Java program that demonstrates the
// Long.numberOfTrailingZeros() function
// negative number
// include lang package
import java.lang.*;

public class GFG {

    public static void main(String[] args)
    {

        long l = -12;

        // returns the number of zero bits following the lowest-order
        // set bit
        System.out.println("Number of trailing zeros = "
                           + Long.numberOfTrailingZeros(l));
    }
}

Output:

Number of trailing zeros = 2

It returns an error message when a decimal a string value is passed as an argument.
Program 3: When a decimal value is passed in argument.

// Java program that demonstrates the
// Long.numberOfTrailingZeros() function
// decimal value as an argument

// include lang package
import java.lang.*;

public class GFG {

    public static void main(String[] args)
    {

        // returns the number of zero bits following the lowest-order
        // set bit
        System.out.println("Number of trailing zeros = "
                           + Long.numberOfTrailingZeros(12.34));
    }
}

Output:

prog.java:16: error: incompatible types: possible lossy conversion from double to long
      System.out.println("Number of trailing zeros = "+Long.numberOfTrailingZeros(12.34));

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

// java program that demonstrates the
// Long.numberOfTrailingZeros() function
// string value as an argument

// include lang package
import java.lang.*;

public class GFG {

    public static void main(String[] args)
    {

        // returns the number of zero bits following the lowest-order
        // set bit
        System.out.println("Number of trailing zeros = "
                           + Long.numberOfTrailingZeros("100"));
    }
}

Output:

prog.java:15: error: incompatible types: String cannot be converted to long
      System.out.println("Number of trailing zeros = "+Long.numberOfTrailingZeros("100"));