complex

#include<iostream>
#include<math.h>
using namespace std;
class complex{
    public:
        complex(double a=0,double b=0);
        complex(double a);
        complex(complex &c);
        void add(complex &c);
        void show();
        double mod();
    private:
        double x;
        double y;
};

complex::complex(double a,double b){
    x=a;
    y=b;
}

complex::complex(complex &c){
    x=c.x;
    y=c.y;
}

void complex::add(complex &c){
    x+=c.x;
    y+=c.y;
}

void complex::show() {
    cout<<x<<'+'<<y<<'i'<<endl;
}

double complex::mod(){
    double m;
    m=sqrt(x*x+y*y);
    return m;
}

int main(){
    complex c1(3,5);
    complex c2=4.5;
    complex c3(c1);
    c1.add(c2);
    c1.show();
    cout<<c1.mod()<<endl;
    return 0;
}