#include <iostream>
using namespace std;
#define PI 3.141592654
int main()
{
    float R;
    cout<<"———————————————————————————————————————————";
    cout<<"\nProgram to calculate the area and circumference of a circle";
    cout<<"\n———————————————————————————————————————————";
    cout<<"\nEnter the radius of a circle ";
    cin>>R;
    cout<<"\nThe area of a circle is "<<PI * R * R;
    cout<<"\nThe circumference of a circle is "<<2 * PI * R;
    cout<<"\n———————————————————————————————————————————\n";
    return 0;
}

kodingwindow@kw:~$ g++ kw.cpp
kodingwindow@kw:~$ ./a.out
———————————————————————————————————————————
Program to calculate the area and circumference of a circle
———————————————————————————————————————————
Enter the radius of a circle 10

The area of a circle is 314.159
The circumference of a circle is 62.8319
———————————————————————————————————————————
kodingwindow@kw:~$