Method and Constructor are working together in c++

Create a suitable situation where Constructor and Method are working together in a class.

Example:

/* The Circle class (All source codes in one file) (CircleAIO.cpp) */
#include <iostream>    // using IO functions
#include <string>      // using string
using namespace std;
 
class Circle {
private:
   double radius;      // Data member (Variable)
   string color;       // Data member (Variable)
 
public:
   // Constructor with default values for data members
   Circle(double r = 1.0, string c = "red") {
      radius = r;
      color = c;
   }
 
   double getRadius() {  // Member function/Method
      return radius;
   }
 
   string getColor() {   // Member function/Method
      return color;
   }
 
   double getArea() {    // Member function/Method
      return radius*radius*3.1416;
   }
};   // need to end the class declaration with a semi-colon
 
// Test driver function or Main Function
int main() {
   // Construct a Circle instance
   Circle c1(1.2, "blue");
   cout << "Radius=" << c1.getRadius() << " Area=" << c1.getArea()
        << " Color=" << c1.getColor() << endl;
 
   // Construct another Circle instance
   Circle c2(3.4); // default color
   cout << "Radius=" << c2.getRadius() << " Area=" << c2.getArea()
        << " Color=" << c2.getColor() << endl;
 
   // Construct a Circle instance using default no-arg constructor
   Circle c3;      // default radius and color
   cout << "Radius=" << c3.getRadius() << " Area=" << c3.getArea()
        << " Color=" << c3.getColor() << endl;
   return 0;
}