http://acm.pku.edu.cn/JudgeOnline/problem?id=1131 八进小数转十进制小数

import java.io.*; import java.util.*; import java.math.*; public class Main { static Scanner in=new Scanner(new BufferedReader(new InputStreamReader(System.in))); public static void main(String[] args){ String tep; BigDecimal one = BigDecimal.valueOf(1); BigDecimal eight = BigDecimal.valueOf(8); while(in.hasNext()){ tep = in.next(); BigDecimal last = one.divide(eight); BigDecimal ans = new BigDecimal(0); int len = tep.length(); for(int i = 2; i < len; i++){ ans = ans.add(last.multiply(new BigDecimal(tep.charAt(i)- '0'))); last = last.divide(eight); } System.out.println(ans); } } }