Java BigInteger pow()方法

java.math.BigInteger. pow(int exponent) 方法用于计算一个BigInteger提高到一些其他数字的幂，这些数字的值等于（这个）指数。 该方法对当前的BigInteger进行运算，该方法被调用时，指数作为参数被传递。

语法：

public BigInteger pow(int exponent)

参数： 此方法接受一个参数 exponent ，即此BigInteger应升至的指数。

返回：

此方法返回一个等于（此）exponent 的BigInteger。

异常：

参数exponent必须是正数（exponent>=0），否则会抛出 ArithmeticException 。

示例：

输入: BigInteger1=321456, exponent=5
输出： 3432477361331488865859403776
解释: BigInteger1.pow(exponent)=3432477361331488865859403776.
321456^5=3432477361331488865859403776

输入: BigInteger1=45321, exponent=3
输出： 93089018611161
解释: BigInteger1.pow(exponent)=93089018611161.
321456^5=93089018611161

下面的程序说明了BigInteger类的pow()方法

例1：

// Java program to demonstrate
// pow() method of BigInteger
 
import java.math.BigInteger;
 
public class GFG {
 
    public static void main(String[] args)
    {
 
        // Creating BigInteger object
        BigInteger b1;
 
        b1 = new BigInteger("321456");
        int exponent = 5;
 
        // apply pow() method
        BigInteger result = b1.pow(exponent);
 
        // print result
        System.out.println("Result of pow operation between BigInteger "
             + b1 + " and exponent " + exponent + " equal to " + result);
    }
}

输出：

Result of pow operation between BigInteger 321456 and exponent 5 equal
to 3432477361331488865859403776

例2：

// Java program to demonstrate
// pow() method of BigInteger
 
import java.math.BigInteger;
 
public class GFG {
 
    public static void main(String[] args)
    {
 
        // Creating BigInteger object
        BigInteger b1;
 
        b1 = new BigInteger("12346");
        int exponent = 6;
 
        // apply pow() method
        BigInteger result = b1.pow(exponent);
 
        // print result
        System.out.println("Result of pow operation between BigInteger "
             + b1 + " and exponent " + exponent + " equal to " + result);
    }
}

输出：

Result of pow operation between BigInteger 41432345678 and exponent 6 equal to 5058679076487529899393537031261743031889730764186441745527485504

例3：

程序显示当作为参数传递的指数小于零时的异常。

// Java program to demonstrate
// pow() method of BigInteger
 
import java.math.BigInteger;
 
public class GFG {
 
    public static void main(String[] args)
    {
 
        // Creating BigInteger object
        BigInteger b1;
 
        b1 = new BigInteger("76543");
        int exponent = -17;
         
        try {
   
        // apply pow() method
        BigInteger result = b1.pow(exponent);
 
        // print result
        System.out.println("Result of pow operation between " + b1
                           + " and " + exponent + " equal to " + result);
          }
        catch (Exception e) {
            System.out.println(e);
        }
 
    }
}

输出：

java.lang.ArithmeticException: Negative exponent

参考： https://docs.oracle.com/en/java/javase/12/docs/api/java.base/java/math/BigInteger.html#pow(int)