请高手指教……
#include "stdio.h"
#include "string.h"
int main ()
{
    long i,j,n,len;
    int base[31];
    base[0] = 1;
    for (i = 1;i < 31;i ++)
        base[i] = 2*base[i - 1] +1;
    char skew[32];
    while (scanf ("%s",skew))
    {
        n = 0;
        if (strcmp(skew,"0") == 0) break;
        len  = strlen (skew);

        j = 0;
        for (i = len -1;i >= 0;i --)
        n += (skew[i] - '0') * base[j++];
        printf ("%ld\n",n);
    }
    return 0;
}