#include
     
      #include
      
       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<
       
        <<'+'<
        
         <<'i'<