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();
	}
}