#include <iostream>

#include <cmath>

using namespace std;

class Complex{

    public:Complex(double real0=,double imaginary0=);

    Complex(Complex &a);

    void add(Complex b);

    void show();

    double mod();

    private:

        double real;

        double imaginary;

};

Complex::Complex(double real0,double imaginary0){

    real=real0;

    imaginary=imaginary0;

}

Complex::Complex(Complex &a){

    real=a.real;

    imaginary=a.imaginary;

}

void Complex::add(Complex b){

    real+=b.real;

    imaginary+=b.imaginary;

}

void Complex::show(){

    cout<<real<<"+"<<imaginary<<"i"<<endl;

}

double Complex::mod(){

    double m;

    m=sqrt(real*real+imaginary*imaginary);

    return m;

}

int main()

{Complex c1(,);

cout<<"c1 = ";

c1.show();

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

 Complex c2(4.5);

 cout<<"c2= ";

 c2.show();

 cout<<"|c2| = " <<c2.mod() <<endl;

 Complex c3(c1);

 c1.add(c2);

 c1.show();

 cout<<c1.mod()<<endl;

}