```
#include<bits/stdc++.h>
using namespace std;
int main(){
double n,a,s=1,s1=1;
cin>>n;
a=sqrt(5);
for(int i=1;i<=n;i++){
s*=(1+a)/2;
s1*=(1-a)/2;
}
printf("%.2lf",(s-s1)/a);
return 0;
}
```
by wrx20100919 @ 2023-11-28 20:15:09
```cpp
#include<bits/stdc++.h>
using namespace std;
int main()
{
double f,g=1,h=1,a;
cin>>a;
for(int i=3;i<=a;i++)
{
f=g+h;
g=h;
h=f;
}
printf("%2.2f",f);
return 0;
}
```
by WangSH2012 @ 2023-11-28 20:16:09
@[ace_12138](/user/997150)
by WangSH2012 @ 2023-11-28 20:16:54
```cpp
#include<bits/stdc++.h>
using namespace std;
int main(){
int a;
cin>>a;
double b=sqrt(5);
double c=(1+b)/2,d=(1-b)/2;
double c1=pow(c,a),d1=pow(d,a);
double e=(c1-d1)/b;
printf("%.2lf",e);
return 0;
}
```
兄弟，可以按照他的公式展开算！！！！！
by wangderui111 @ 2024-02-05 17:08:48