poj 1131 Octal Fractions（高精度小数进制转换） Java

import java.math.BigDecimal;
import java.math.RoundingMode;
import java.util.Scanner;
public class Main {
  public static void main(String[] args) {
    Scanner cin = new Scanner(System.in);
    String str, ors;
    BigDecimal x, y, z;
    while (cin.hasNext()) {
      ors = cin.next();
      str = ors.substring(ors.indexOf(".")+1, ors.length());
      z = new BigDecimal(0);
      y = new BigDecimal(1);
      for (int i = 0; i < str.length(); i++) {
        x = new BigDecimal(str.charAt(i) - '0');
        y = y.multiply(new BigDecimal(8));
        x = x.divide(y, str.length()*3, RoundingMode.HALF_UP);
        z = z.add(x);
      }
      System.out.println(ors + " [8] = " + z + " [10]");
    }
    cin.close();
  }
}