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

加入一下吧！

#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; }

不关注我就要~~~

#include <iostream> using namespace std; double pi=3.14159,r,a,b,c; char d=' '; int main() { cin>>r; a=2 * r; b=2* pi * r; c=pi * r * r; printf("%.4f%.c%.4f%.c%.4f",a,d,b,d,c); 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; }

这题不建议抄题解，不然先去做同提单的前几题吧