怎么会出现这个错误？解答一下

Question

Answer 1

import java.util.Scanner;

import static java.lang.Math.pow;

class transformation {
    public double A(double x) {
        int y = (int) x;
        int a, b, c = 1, d, sum = 0;
        while (y >= 1) {
            a = y / 2;
            b = y % 2;
            y = a;
            d = c * b;
            c = c * 10;
            sum = sum + d;
        }
        int i = 1, b1;
        double sum1 = 0;
        double f = x - (int) x, a1, c1 = 0.1, d1;
        while (f != 0) {
            a1 = f * 2;
            b1 = (int) a1;
            f = a1 - b1;
            d1 = c1 * b1;
            c1 = c1 * 0.1;
            sum1 = sum1 + d1;
            i++;
            if (i == 5) {
                break;
            }
        }
        return sum + sum1;
    }

    public double B(String N) {
        double sum = 0;
        int j = 1, n = 1;
        int pIndex = N.indexOf('.');
        if (pIndex == -1) {
            for (int i = N.length() - 1; i >= 0; i--) {
                int x = N.charAt(i) - '0';
                sum = sum + x * pow(2, N.length() - 1 - i);
            }
            sum = (int) sum;
        } else {
            for (int i = pIndex + 1; i < N.length(); i++) {
                int x = N.charAt(i) - '0';
                sum = sum + x * pow(2, pIndex - i);
            }
            for (int i = pIndex - 1; i >= 0; i--) {
                int x = N.charAt(i) - '0';
                sum = sum + (int) (x * pow(2, pIndex - i - 1));
            }
        }
        return sum;
    }

}

public class Test {
    public static void main(String[] args) {
        Scanner reader = new Scanner(System.in);
        transformation me = new transformation();
        System.out.println("请选择操作:1,十进制转二进制 2,二进制转十进制");
        int a = reader.nextInt();
        for (; a != 1 && a != 2; ) {
            System.out.println("输入错误，请重新输入");
            a = reader.nextInt();
        }
        if (a == 1) {
            System.out.println("请输入一个十进制数");
            double b = reader.nextDouble();
            System.out.println("这个数的二进制数为:" + me.A(b));
        }
        if (a == 2) {
            System.out.println("请输入一个二进制数");
            String c = reader.next();
            System.out.println("这个数的十进制数为:" + me.B(c));
        }
    }
}