问java中数字2^1000的位数和

EN

import java.math.*;

public class PowerDigitSum {
    public static void main(String[] args) {
        double[] digits ;
        digits = new double[302];
        double i = Math.pow(2, 1000);
        double c = 301;
        double c1 = 0;
        double d = 0;
        while(c>=0) {
            c1 = Math.pow(10, c);
            d = Math.floor(i/c1);
            i = i - d*c1;
            digits[(int)c] = (int)d;
            c = c-1;
        }
        double sum = 0;
        c = 0;
        while (c<302) {
            sum = sum+digits[(int)c];
            c= c+1;
        }
        System.out.println(sum);
    }
}