View Code of Problem 71

#include <stdio.h>
int main(){
  int n;
  scanf("%d",&n);
  int i;
  double f1=1,f2=2,f3,sum=f2/f1;
  for(i=0;i<n-1;i++){
    f3=f1+f2;
    sum+=f3/f2;
    f1=f2;
    f2=f3;
   
  }
  printf("%.2f\n",sum);
  
  
  
  
  return 0;
}