#include <iostream>#include <cmath>using namespace std;class Circle{private: double x; double y; double r;public: Circle(); Circle(double xCo, double yCo, double rad); double area(); double centre_dist(Circle & c); bool istouch(Circle & c);};Circle::Circle(){ cout << "Enter x coord: "; cin >> x; cout << "Enter y coord: "; cin >> y; cout << "Enter radius: "; while (cin >> r && r < 0) { cout << "Radius can't be negative"; cout << "Enter radius: "; }}Circle::Circle(double xCo, double yCo, double rad) : x(xCo), y(yCo), r(rad){ if (r < 0) { cout << "Radius can't be negative"; cout << "Radius set to 0"; r = 0; }}double Circle::area(){ return 3.1415926 * r * r;}double Circle::centre_dist(Circle & c){ return sqrt((x - c.x) * (x - c.x) + (y - c.y) * (y - c.y));}bool Circle::istouch(Circle & c){ return (this->centre_dist(c) <= r + c.r) ? true : false;}int main(){ Circle c1; Circle c2(0, 0, 5); cout << "area of c2: " << c2.area() << endl; cout << "centre distance: " << c2.centre_dist(c1) << endl; cout << "is touch: "; c2.istouch(c1) ? cout << "yes" : cout << "no"; cout << endl; return 0;}