UVA 575 (暑假-数论 -A - Skew Binary)

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

int main() {
char str[1000];
while (gets(str) && str[0] != '0') {
int sum = 0;
int len = strlen(str);
for (int i = 1; i <= len; i++) {
sum += (str[len - i] - '0') * (pow(2, i) - 1);
}
printf("%d\n", sum);
}
return 0;
}