#include "math.h"
#include <string.h>
#include  <stdlib.h>
int  rint (double value){
    return (int) (floor(value*2)-floor(value));
}

/*算法开始*/
char* getCode(char* source)
 {
    int i,len;
  int aMod,sum,Wi;
  char* myx=(char*)malloc(1);
  int m_table[11]= {1,0,0,9,8,7,6,5,4,3,2};
  int li_round,li_b,amod;
  sum = 0;
  len = strlen(source);
  if(len==0){
      return "-1";
  }
  for(i=1;i<len+1;i++){
     double temp=exp(len-i+1);
     double templog=log(2);
      li_round=rint(exp((len-i+1)*log(2)));
      Wi =(int) fmod(li_round,11);
      li_b=source[i-1];
      sum+=Wi*(li_b-'0');
  }
    amod=(int) fmod(sum,11);
    if( amod == 2) {
        myx = "X";
    }
    else {
        aMod = m_table[amod];
        /*把整型转化成字符*/
        sprintf(myx,"%d", aMod); 
    }
    return myx;
}

package com;

public class Test {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Test test = new Test();
        System.out.println(test.getCode("072261793"));
    }
    
    private int rint (double value){
        return (int)(Math.floor(value*2)-Math.floor(value));
    }
    
    private String getCode(String source){
        int len = 0;
        int sum = 0;
        int Wi = 0;
        String myx = "";
        int[] m_table = {1,0,0,9,8,7,6,5,4,3,2};
        int li_round = 0;
        int li_b = 0;
        int amod = 0;
        sum = 0;
        len = source.length();
        if(len == 0){
            return "-1";
        }
        for(int i = 1; i < len + 1;i++){
            li_round = rint(Math.exp((len - i + 1) * Math.log(2)));
            Wi = li_round/11;
            li_b = source.charAt(i-1);
            sum += Wi*(li_b - '0');
        }
        amod = sum/11;
        if(amod == 2) {
            myx = "X";
        }
        else {
            myx = String.valueOf(m_table[amod]);
        }
        return myx;
    }
}