<C++>80分求助

#include<cstdio>
int main()
{
    float a,e;
    scanf("%f",&a);
    int b,c,d,f;
    b = a/100;
    c = (a-100*b) / 10;
    d = a-100*b-10*c;
    e = a-100*b-10*c-d;
    f = 10*e;   
    printf("%.3f",f+0.1*d+0.01*c+0.001*b);
    return 0;
}