翁恺慕课C语言练习4.2

#include <stdio.h>
#include <stdlib.h>
#include <math.h>
int main()
{
    int a = 0,b = 1,c = 0;
    scanf("%d",&a);
    do
    {
        if((a%10)%2==(b%2))
        {
            c = c + pow(2,(b-1));
        }
        b++;
        a = a/10;
    }while(a>0);
    printf("%d",c);
    return 0;
}