进制的转换 不知道那里错了

[loulanhaojie]

写了一段代码 是把0到1之间的8进制数转化为十进制数的
import java.util.*;
public class Test3 {
public Test3(){
Scanner in = new Scanner(System.in);
double m = in.nextDouble();
String s = String.valueOf(m);
double e = (double)1/8;
double total =0.00;
for(int i = 2;i<s.length();i++){
total += (s.charAt(i)-48)*e;
e *= e;
}
System.out.println(total);
}
public static void main(String[] args){
new Test3();
}
}
执行的时候发现有时会出错
比如0.001
0.01234567
不知道如何改进
请各位给点意见
谢谢
~~

[heruoyong]

e *= e;
e *= (double)1/8;

[heruoyong]

import java.util.*;

public class Test3 {

	public Test3() {
		Scanner in = new Scanner(System.in);
		double m = in.nextDouble();
		
		double total = 0.00;
		if (m > 0 & m < 1) {
			String s = String.valueOf(m);
			double e = (double) 1 / 8;
			
			for (int i = 2; i < s.length(); i++) {
				total += (s.charAt(i) - 48) * e;
				e *= (double)1/8;
			}
		}
		System.out.println(total);
	}

	public static void main(String[] args) {
		new Test3();
	}
}

[loulanhaojie]

有更简洁的代码吗？？
有的话给个吧
~~

[loulanhaojie]

刚试了下 你输入0.0001试试
结果是
0.3232421875

[明留]

e *= (double)1/8;

[heruoyong]

package mars.test;

import java.util.*;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class ConvertOctalToDecimal {

	public static final String EMode="^(\\d)\\.(\\d)E-(\\d+)$";
	
	
	public ConvertOctalToDecimal() {
			
		Scanner in = new Scanner(System.in);
		double m = in.nextDouble();

		double e = 0.125d;
		double total = 0.00d;
		if (m > 0 & m < 1) {
			//0.001=1.0E-4
			String s = String.valueOf(m);
			
			if(Pattern.matches(EMode,s))
			{
				Matcher matcher = Pattern.compile(EMode).matcher(s);
				String one=null;
				String two=null;
				String three=null;
				
				while(matcher.find())
				{
					one = matcher.group(1);
					two = matcher.group(2);
					three = matcher.group(3);
				}
				//
				total=Integer.parseInt(one)*1d;
				
				for(int i=0;i<two.length();i++)
				{
					total +=(s.charAt(i) - 48)*e;
					e*=0.125d;
				}
				total*=Math.pow(8d,-Integer.parseInt(three));
			}
			else
			{
				for (int i = 2; i < s.length(); i++) {
			  			total += (s.charAt(i) - 48)*e;
						e *= 0.125d;
					}
			}
		}
		System.out.println(total);
	}

	public static void main(String[] args) {
		 new ConvertOctalToDecimal();
	 
	}
}

[heruoyong]

//0.0001=1.0E-4
String s = String.valueOf(m);

出问题就在这里,主要是当为0.0001的时候,s为1.0E-4了,所以这里分两种情况来做这件事情