PTA——数列求和

程序：

 #include<stdio.h>

 int main() {
     int i,n;
     double fz = ,fm = ,sum = ;
     scanf("%d",&n);
     double s = ;
     for(i = ; i <= n; i++) {
         fm = fz;
         fz = sum;
         sum = fz + fm;
         s += fz/fm;
     }
     printf("%0.2lf",s);
 }