C++ program to demonstrate INLINE FUNCTION to calculate area of a circle from its radius

#include <iostream>
#define PI 3.1416
using namespace std;
inline float area(float r)
{
    return PI*r*r;
}
int main()
{
    float r;
    cout<<"Enter radius of a circle: ";
    cin>>r;
    cout<<"Area of the circle is "<<area(r);
    return 0;
}