- shilinhan's blog
与圆相关的计算
- 2024-2-19 14:59:43 @
#include <bits/stdc++.h>
using namespace std;
int main() {
const double PI = 3.14159;
double r;
cin >> r;
cout << fixed << setprecision(4)
<< 2 * r << " " << 2 * PI * r << " "
<< PI * r * r << endl;
return 0;
}