public class Decimal {
        private Node startOfInteger;
        private Node startOfFraction;
        public Decimal plus(Decimal y){
                
        }
        public Decimal(double d){
                if(d<0)
                        throw new IllegalArgumentException(d+"<0");
                startOfInteger = new Node((int)d%10);
                startOfFraction = new Node((int)d%1);
                Node p = startOfInteger;
                Node q = startOfFraction;
                d /= 10;
                while(d>0){
                        p = p.next = new Node((int)d%10);
                        q = q.next = new Node((int)d%1*10);
                        d /= 10;
                }
        }
        public Decimal(String s){
                if(s.length()==0)
                        throw new IllegalArgumentException("empty string");
                 startOfInteger = new Node(digit(s,s.length() = 1));
                Node p = startOfInteger;
                for(int i = s.length()-2;i>=0;i--)
                        p = p.next = new Node(digit(s,i));
        }
        private int digit(String s,int i){
                String ss = s.substring(i,i+1);
                return Integer.parseInt(ss);
        }
        public int devide(double d){
                String a = d +"";
        }
        public String toString(){
                        StringBuffer buf =new StringBuffer(Integer.toString(start.digit));
                        Node p =startOfInteger.next;
                        while(p!=null){
                                buf.insert(0,Integer.toString(p.digit));
                                p = p.next;
                        }
                        return buf.toString();                
        }
        private class Node{

                private int data;
                private Node next;

                public Node(int data) {
                        this.data = data;

                }

                public Node(int data, Node next) {
                        this.data = data;
                        this.next = next;
                }
                
        }

}
일단 대충 이정도는 해놨는데 여기서 진행이 안되요 제발 고수님들 도와주세요 ㅜㅜㅜ