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Java lang.Long.numberOfLeadingZeros() method in Java with Examples
  • Last Updated : 23 May, 2019


java.lang.Long.numberOfLeadingZeros() is a built-in function in Java which returns the number of leading zero bits to the left of the highest order set bit. In simple terms, it returns the (64-position) where position refers to the highest order 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 numberOfLeadingZeros(long num)
Parameters:
num - the number passed 
Returns:
the number of leading zeros before the highest-order set bit

Examples:

Input : 8
Output : 60
Explanation: Binary representation of 8 is 1000 
No of leading zeros to the left of the highest-order set
bit is 60. 

Input : 25
Output : 59

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

Program 1:






// Java program that demonstrates the
// Long.numberOfLeadingZeros() 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 before the highest-order
        // set bit
        System.out.println("Number of leading zeros = "
                           + Long.numberOfLeadingZeros(l));
  
        // second example
        l = 25;
        System.out.println("Number of leading zeros = "
                           + Long.numberOfLeadingZeros(l));
    }
}

Output:

Number of leading zeros = 60
Number of leading zeros = 59

Note: In case of a negative number, every number will have 0 leading zeros.

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




// Java program that demonstrates the
// Long.numberOfLeadingZeros() 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 before the highest-order
        // set bit
        System.out.println("Number of leading zeros = "
                           + Long.numberOfLeadingZeros(l));
  
        l = -100;
        System.out.println("Number of leading zeros = "
                           + Long.numberOfLeadingZeros(l));
    }
}

Output:

Number of leading zeros = 0
Number of leading zeros = 0

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




// Java program that demonstrates the
// Long.numberOfLeadingZeros() function
// decimal number
// include lang package
import java.lang.*;
  
public class GFG {
  
    public static void main(String[] args)
    {
  
        // returns the number of zero bits before the highest-order
        // set bit
        System.out.println("Number of leading zeros = "
                           + Long.numberOfLeadingZeros(10.45));
    }
}

Output:

prog.java:16: error: incompatible types: possible lossy conversion from double to long
                           + Long.numberOfLeadingZeros(10.45));

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




// Java program that demonstrates the
// Long.numberOfLeadingZeros() function
// string number
// include lang package
import java.lang.*;
  
public class GFG {
  
    public static void main(String[] args)
    {
  
        // returns the number of zero bits before the highest-order
        // set bit
        System.out.println("Number of leading zeros = "
                           + Long.numberOfLeadingZeros("10"));
    }
}

Output:

prog.java:16: error: incompatible types: String cannot be converted to long
                           + Long.numberOfLeadingZeros("10"));

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