acm 10929 You can say 11

 [心得]
    if((abs(odd-even))%11==0)  ,(abs(odd-even)) 記得要括弧,不然會一直錯!


#include <stdio.h>
#include <string.h>
#include <math.h>

char s[1002];

int main()
{
  while(gets(s))
  {
    int i,length,num;
    int odd=0,even=0;
    if(s[0]=='0'&& s[1]=='\0')
      break;
   
    length =strlen(s);               
    for(i=0;i<length;i++)
    {              
      if((i%2)== 1) /*奇數位元*/
        odd += s[i]-48;
      else        /*偶數位元*/
        even+= s[i]-48;                         
    }
  
    if((abs(odd-even))%11==0)
      printf("%s is a multiple of 11.\n",s);
    else 
      printf("%s is not a multiple of 11.\n",s);        
                   
  } 
 
 system("pause");
 return 0;   
}