#include<bits/stdc++.h>

using namespace std;

int main()

{

double w,h,l,a;

cin >> w;

if(w == w)

{

h=2*w;

l=h*3.14159;

a=w*w * 3.14159;

printf("%.4f %.4f %.4f",h,l,a);

}

}

#include<bits/stdc++.h> using namespace std; int main() { double w,h,l,a; cin >> w; if(w == w) { h=2w; l=h3.14159; a=w*w * 3.14159; printf("%.4f %.4f %.4f",h,l,a); } }

#include<iostream>
#include<iomanip>
#include<math.h>
using namespace std;
int main(){
	double r,d,c,s;
	cin>>r;
	d=r*2;
	c=d*3.14159;
	s=r*r*3.14159;
	cout<<fixed<<setprecision(4)<<d<<" ";
	cout<<fixed<<setprecision(4)<<c<<" ";
	cout<<fixed<<setprecision(4)<<s;
}

#include<iostream> #include<iomanip> #include<cmath> using namespace std; int main() { double a,b,c,d; cin>>a; b=2.0a; c=2a3.14159; d=aa*3.14159; cout<<fixed<<setprecision(4)<<b<<" "; cout<<fixed<<setprecision(4)<<c<<" "; cout<<fixed<<setprecision(4)<<d; return 0; } 挺简单的

#include<iostream> #include<iomanip> #include<cmath> using namespace std; int main() { double n,z,c,s; cin>>n; z=2.0n; c=2n3.14159; s=nn*3.14159; cout<<fixed<<setprecision(4)<<z<<" "; cout<<fixed<<setprecision(4)<<c<<" "; cout<<fixed<<setprecision(4)<<s;

return 0;

}

#include<bits/stdc++.h> using namespace std; int main(){ double r; cin>>r; double d,c,s; d=2r; c=23.14159r; s=3.14159pow(r,2); printf("%.4lf %.4lf %.4lf",d,c,s); return 0; }

#include<iostream> #include<iomanip> #include<math.h> using namespace std; int main(){ double r,d,c,s; cin>>r; d=r2; c=d3.14159; s=rr3.14159; cout<<fixed<<setprecision(4)<<d<<" "; cout<<fixed<<setprecision(4)<<c<<" "; cout<<fixed<<setprecision(4)<<s; }

#include<bits/stdc++.h>
using namespace std;
int main()
{
	double r,zhi,z,c;
	cin >> r;
	if(r == r)
	{
		zhi=2*r;
		z=zhi*3.14159;
		c=r*r * 3.14159;
		printf("%.4f %.4f %.4f",zhi,z,c); 
	}
}

#include<stdio.h> #include<iostream> using namespace std; int main() { double a,b,c,d,pi; cin>>a; pi=3.14159; b=a2; printf("%.4lf ",b); c=pib; printf("%.4lf ",c); d=piaa; printf("%.4lf ",d); }