@[sunbinbin](/user/750720) pi的近似值等于3.14159
by hexuchen @ 2023-09-17 15:39:54
@[sunbinbin](/user/750720)
```cpp
#include <bits/stdc++.h>
using namespace std;
const double pi = 3.14159; //这里改成3.14159
int main() {
double r;
double d, s, c;
cin >> r;
d = r * 2;
s = pi * r * r;
c = r * 2 * pi;
printf("%.4lf %.4lf %.4lf", d, c, s);
return 0;
}
```
by hexuchen @ 2023-09-17 15:40:41
@[sunbinbin](/user/750720) 求关注
by hexuchen @ 2023-09-17 15:40:54
好哇
by sunbinbin120808 @ 2023-09-17 15:41:20
已关注
by sunbinbin120808 @ 2023-09-17 15:42:59
@[sunbinbin](/user/750720)
```cpp
#include<bits/stdc++.h>
using namespace std;
double a , p = 3.14159;
int main()
{ cin >> a;
cout << fixed << setprecision(4) << a*2 <<" " << a*2*p <<" " << a*a*p;
return 0;
}
```
by ljk654321 @ 2023-12-06 16:34:10