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

加入一下吧！

#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

#include<iostream> #include<cstdio> using namespace std; int main(){ double a; cin>>a; double z,c,m; z=a2; c=a23.14159; m=aa*3.14159; printf("%.4f",z); cout<<" "; printf("%.4f",c); cout<<" "; printf("%.4f",m); }

#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; }