The method floorPowerOfTwo(BigInteger x) of Guava’s BigIntegerMath class returns the largest power of two less than or equal to x. This is equivalent to BigInteger.valueOf(2).pow(log2(x, FLOOR)).
Syntax:
public static BigInteger floorPowerOfTwo(BigInteger x)
Parameters: This method takes the BigInteger x as parameter whose floor power of two is to be found.
Return Value: This method returns the largest power of two less than or equal to x.
Exceptions: This method throws IllegalArgumentException if x <= 0.
Below examples illustrates the BigIntegerMath.floorPowerOfTwo() method:
Example 1:
// Java code to show implementation of // floorPowerOfTwo() method // of Guava's BigIntegerMath class import java.math.*;
import com.google.common.math.BigIntegerMath;
class GFG {
// Driver code
public static void main(String args[])
{
BigInteger n1 = BigInteger.valueOf( 10 );
// Using floorPowerOfTwo(BigInteger x) method
// of Guava's BigIntegerMath class
BigInteger
ans1
= BigIntegerMath.floorPowerOfTwo(n1);
System.out.println( "Largest power of 2 less "
+ "than or equal to " + n1
+ " is: " + ans1);
BigInteger n2 = BigInteger.valueOf( 127 );
// Using floorPowerOfTwo(BigInteger x) method
// of Guava's BigIntegerMath class
BigInteger
ans2
= BigIntegerMath.floorPowerOfTwo(n2);
System.out.println( "Largest power of 2 less "
+ "than or equal to " + n2
+ " is: " + ans2);
}
} |
Output:
Largest power of 2 less than or equal to 10 is: 8 Largest power of 2 less than or equal to 127 is: 64
Example 2: To show IllegalArgumentException
// Java code to show implementation of // floorPowerOfTwo(BigInteger x) method // of Guava's BigIntegerMath class import java.math.*;
import com.google.common.math.BigIntegerMath;
class GFG {
// Driver code
public static void main(String args[])
{
try {
BigInteger n1 = BigInteger.valueOf(- 3 );
// Using floorPowerOfTwo(BigInteger x) method
// of Guava's BigIntegerMath class
// This should raise "IllegalArgumentException"
// as x <= 0
BigInteger
ans1
= BigIntegerMath.floorPowerOfTwo(n1);
System.out.println( "Largest power of 2 less "
+ "than or equal to " + n1
+ " is: " + ans1);
}
catch (Exception e) {
System.out.println( "Exception: " + e);
}
}
} |
Output:
Exception: java.lang.IllegalArgumentException: x (-3) must be > 0