HTRON C++

#include <bits/stdc++.h>
using namespace std;

float r,s,p,pi=3.14;
int main()
{
    freopen("HTRON.inp","r", stdin);
    freopen("HTRON.out","w", stdout);  
    cin >> r;
    s = r*r*pi;
    p = r*2*pi;
    cout<<fixed << setprecision(2);
    cout << "Chu vi la: " << p << endl;
    cout << "Dien tich la: " << s;
}