OpenJudge 2973 Skew数

#include<stdio.h>
int main()
{
int i,s,t,sum;
char skew[32];
while(scanf("%s",skew))
{
for(sum=t=i=0;skew[i];i++)
{
sum=(sum<<1)+skew[i]-'0';
t+=skew[i]-'0';
}
sum=(sum<<1)-t;
if(!sum)  break;
printf("%d\n",sum);
}
return 0;
}