Java 番石榴| long math . checked Dow(long b,int k)方法,带示例

原文:https://www . geesforgeks . org/Java-guava-long math-checkedpowlong-b-int-k-method-with-examples/

checkedPow(长 b,长 k) 是番石榴 LongMath Class 的一种方法,接受两个参数 bk ,用来求 b 的 k 次方。

语法:

public static long checkedPow(long b, long k)

参数:该方法接受两个参数,b 和 k,参数 b 称为,加到 k 次幂。

返回值:此方法返回 b 的 k 次幂。

异常:如果 b 的 k 次方在有符号长算术中溢出,方法 checkedPow(长 b,长 k)抛出 算术异常

以下示例说明了上述方法的实现:

例 1:

// Java code to show implementation of
// checkedPow(long b, long 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 = 5;
        int k1 = 7;

        // Using checkedPow(long b, long k) method
        // of Guava's LongMath class
        long ans1 = LongMath.checkedPow(b1, k1);

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

        long b2 = 19;
        int k2 = 4;

        // Using checkedPow(long b, long k) method
        // of Guava's LongMath class
        long ans2 = LongMath.checkedPow(b2, k2);

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

输出:

5 to the 7th power is: 78125
19 to the 4th power is: 130321

例 2:

// Java code to show implementation of
// checkedPow(long b, long 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 checkedPow(long b, long k) method of
            // Guava's LongMath class
            // This should raise "ArithmeticException" as
            // b to the kth power overflows in
            // signed long arithmetic
            long ans = LongMath.checkedPow(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 = 20;
        int k = 25;

        try {

            // Function calling
            findPow(b, k);
        }
        catch (Exception e) {
            System.out.println(e);
        }
    }
}

输出:

java.lang.ArithmeticException: overflow

参考:https://Google . github . io/guava/releases/20.0/API/docs/com/Google/common/math/longmath . html # checked Dow-long-int-