java - Math.pow(23,29)%91 的结果为什么是错误的？

Question

Math.pow(23,29)%91 的结果为什么是错误的？

public class T1 {

    public static void main(String[] args) {

        double c = Math.pow(23,29)%91.0;

        System.out.println(c);
    }

}

输出：28.0


        int c = (int)Math.pow(23,29)%91;

        System.out.println(c);

输出  36

然而这都不是正确答案

正确取余后的值是4才对

Answer 1

Insufficient precision, 23 ^ 29是个40位Decimal number,

• doubleThere are only 15 significant digits, so the exact value at the end cannot be expressed at all

• intThe maximum value is only 10 digits, so the assignment has already overflowed

Answer 2

Double is a floating point number. It is best to use BigInteger to solve your problem.