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

#include<bits/stdc++.h> using namespace std; int main() { double a; cin>>a; printf("%.4f",a2); cout<<" "; printf("%.4f",a23.14159); cout<<" "; printf("%.4f",aa*3.14159); return 0; }

#include <iostream> #include <iomanip> // 用于设置输出的精度 using namespace std; int main() { const double PI = 3.14159; // 定义PI常量 double r; // 圆的半径 }

#include<iostream> #include<iomanip> #include<cmath> using namespace std; int main(){ double r; cin>>r; cout<<std::fixed<<setprecision(4)<<r2<<" "<<r23.14159<<" "<<rr*3.14159; return 0; }

#include <bits/stdc++.h> using namespace std; int main(){ double r,PI=3.14159; cin>>r; printf("%.4f ",r2); printf("%.4f ",r2PI); printf("%.4f ",rr*PI); return 0; }

#include<bits/stdc++.h> using namespace std; int main() { double a; cin>>a; double z=a2; double c=a23.14159; double s=aa3.14159; cout<<fixed<<setprecision(4)<<z<<" "<<fixed<<setprecision(4)<<c<<" "<<fixed<<setprecision(4)<<s; return 0; } //如果圆的半径是r，那么圆的直径、周长、面积分别是r2，r2PI，rrPI //约定PI=3.14159csa