#include <iostream>
using namespace std;
#define PI 3.14159
#define NEWLINE '\n'
int main ()
{
double r=5.0; // radius
double circle;
circle = 2 * PI * r;
cout << circle;
cout << NEWLINE;
return 0;
}
i mean thigns like this :P
this is to measure the cricumfrence of a circul that has 5 inch of redius :P
it will be 31.4159
ill show up on cmd