y

guqingchen

[C++] 纯文本查看 复制代码

#include<bits/stdc++.h>
using namespace std;
int main(){
/*	float a,b;
	double c;
    cin>>a>>b;
    c=(double)a/b;
    cout<<fixed<<setprecision(9)<<c<<endl;*/
	float r;
	double a,b,c;
	scanf("%f",&r);
	a=2*r;
	b=a*3.1415926;
	c=r*r*3.1415926;
	printf("%0.4f %0.4f %0.4f",a,b,c);
}