Operator Overloading Program in C++

#include <iostream>
using namespace std;
 
class Circle {
    private:
        float radius;
    public:
        Circle(float r = 0) : radius(r) { }
        void changeRadius(int radius) { this->radius = radius; }
        float getRadius() { return radius; }
        float getArea() const { return 3.14 * radius * radius; }
        bool operator==(Circle a);
};
 
inline bool Circle::operator==(Circle a)
{
    return this->radius == a.radius;
}
 
int main()
{
    Circle A(10), B(20), C(10);
 
    cout << "Circle A : Radius = " << A.getRadius() << " units, Area = "
         << A.getArea() << " sq. units\n";
    cout << "Circle B : Radius = " << B.getRadius() << " units, Area = "
         << B.getArea() << " sq. units\n";
    cout << "Circle C : Radius = " << C.getRadius() << " units, Area = "
         << C.getArea() << " sq. units\n";
    cout << "A == B : ";
    if (A == B)
        cout << "Circles are equal.\n";
    else
        cout << "Circles are not equal.\n";
    cout << "A == C : ";
    if (A == C)
        cout << "Circles are equal.\n";
    else
        cout << "Circles are not equal.\n";
}

Output:
Circle A : Radius = 10 units, Area = 314 sq. units
Circle B : Radius = 20 units, Area = 1256 sq. units
Circle C : Radius = 10 units, Area = 314 sq. units
A == B : Circles are not equal.
A == C : Circles are equal.