这么简单||ヽ(*￣▽￣*)ノミ|Ю

#include<bits/stdc++.h>
using namespace std;
int main(){
double r,pi=3.14159;
cin>>r;
printf("%.4f",r2);
cout<<" ";
printf("%.4f",r2pi);
cout<<" ";
printf("%.4f",rr*pi);
return 0;
}