poj1565-Skew Binary

#include<stdio.h>
#include<string.h>
#include<math.h>
int main(void) {
char n[32];
while(1) {
scanf("%s",&n);
int len = strlen(n);
long ret = 0;
if(len==1 && n[0]=='0') break;
for(int i=0,j=len;i<len;i++,j--) {
long x = (long)n[i]-'0';
ret += x*(pow(2,j)-1);
}
printf("%d\n",ret);
}
}