Java Guava | pow(long b, int k) of LongMath Class with Examples

The method pow(long b, int k) of Guava’s LongMath Class returns b to the kth power. Even if the result overflows, it will be equal to BigInteger.valueOf(b).pow(k).longValue(). This implementation runs in O(log k) time.

Syntax:

public static long pow(long b, int k)

Parameters: The method accepts two parameters, b and k. The parameter b is called base which is raised to the k-th power.

Return Value: This method returns the k-th power of b.

Exception: This method throws IllegalArgumentException if k is negative.

Example 1:

// Java code to show implementation of
// pow(long b, int k) method of Guava's
// LongMath Class

import java.math.RoundingMode;
import com.google.common.math.LongMath;

class GFG {

    // Driver code
    public static void main(String args[])
    {
        long b1 = 4;
        int k1 = 5;

        long ans1 = LongMath.pow(b1, k1);

        System.out.println(b1 + " to the " + k1
                           + "th power is: "
                           + ans1);

        long b2 = 12;
        int k2 = 3;

        long ans2 = LongMath.pow(b2, k2);

        System.out.println(b2 + " to the " + k2
                           + "rd power is: "
                           + ans2);
    }
}

Output:

4 to the 5th power is: 1024
12 to the 3rd power is: 1728

Example 2:

// Java code to show implementation of
// pow(long b, int k) method of Guava's
// LongMath class

import java.math.RoundingMode;
import com.google.common.math.LongMath;

class GFG {

    static long findPow(long b, int k)
    {
        try {
            // Using pow(long b, int k)
            // method of Guava's LongMath class
            // This should throw "IllegalArgumentException"
            // as k < 0
            long ans = LongMath.pow(b, k);

            // Return the answer
            return ans;
        }
        catch (Exception e) {
            System.out.println(e);
            return -1;
        }
    }

    // Driver code
    public static void main(String args[])
    {
        long b = 4;
        int k = -5;

        try {
            // Using pow(long b, int k)
            // method of Guava's LongMath class
            // This should throw "IllegalArgumentException"
            // as k < 0
            LongMath.pow(b, k);
        }
        catch (Exception e) {
            System.out.println(e);
        }
    }
}

Output:

java.lang.IllegalArgumentException: exponent (-5) must be >= 0

Reference: https://google.github.io/guava/releases/20.0/api/docs/com/google/common/math/LongMath.html#pow-long-int-