#include<iostream>

#include<cmath>

using namespace std;

class Complex

{

    public:

        Complex (double xx=,double yy=):x(xx),y(yy){}

        Complex (Complex &c):x(c.x),y(c.y){}

        void show()

        {

            cout<<x<<"+"<<y<<"i"<<endl;

        }

        void add(Complex &c)

        {

             x=x+c.x;

            y=y+c.y;

        }

        double mod()

        {

            double m=sqrt(x*x+y*y);

            return m;

        }

    private:

        double x,y;

 } ;

 int main ()

 {

     Complex c1(,);

     cout<<"c1=";

     c1.show();

     cout<<"|c1|="<<c1.mod()<<endl;

     Complex c2(4.5);

     cout<<"c2=";

     c2.show();

     Complex c3(c1);

     cout<<"c3=";

     c3.show();

     c1.add(c2);

     cout<<"|c2|=";

     c1.show();

    return ;

 }