#include<iostream>
#include<cmath>
using namespace std;

class sp
{
private:
   double th;
   double ao;
public:
   sp();
   sp(double th);
   sp(double th,double a);
   void nhap();
   void xuat()const {
      if (ao>=0)
               cout<<th<<" + "<<ao<<"i"<<endl;
       else
               cout<<th<<" - "<<abs(ao)<<"i"<<endl;
         }
   double tinhchuan();
   sp cong(sp p);
   void setthuc(double thuc){th=thuc;}
   double getthuc(){return th;}
   void setao(double a){ao=a;}
   double getao(){return ao;}
};
sp::sp()
{
   th=0;
   ao=0;
}
sp::sp(double thuc)
{
   th=thuc;
   ao=0;
}
sp::sp(double thuc,double a)
{
   th=thuc;
   ao=a;
}
void sp::nhap()
{
   cout<<"nhap vao phan thuc= ";
   cin>>th;
   cout<<"nhap vao phan ao= ";
   cin>>ao;
}
/*double sp::xuat()
{
   cout<<th<<" + "<<ao<<"i "<<endl;  //khúc này gõ thế nào nó cũng báo lỗi ghét quá bỏ lên trên kia lun
}*/
double sp::tinhchuan()
{
   return sqrt(th*th+ao*ao);
}
sp sp::cong(sp p)
{
   sp q;
   q.th=th+p.th;
   q.ao=ao+p.ao;
   return q;
}
int main()
{
   sp s1;
   s1.xuat();
   s1.setthuc(2);
   s1.setao(3);
   s1.xuat();
   sp s2(3,-4);
   s2.xuat();
   sp tg;
   tg=s1.cong(s2);
   tg.xuat();
   double tc=tg.tinhchuan();
   cout<<tc<<endl;
   sp s3;
   s3.nhap();
   s3.xuat();

   system("pause");
   return 0;
}

#include<iostream>
#include<cmath>
using namespace std;


class SP{
private:
 double t,a;
public:
 SP();
 SP(double thuc);
 SP(double thuc, double ao);
 void xuat()const;
 void nhap();
 double tinhchuan();
 SP cong(SP p);
 void setthuc(double thuc);
 void setao(double ao);
 double getthuc();
 double getao();
};
SP::SP()
{
 t=0;
 a=0;
}
SP::SP(double thuc)
{
 t=thuc;
 a=0;
}
SP::SP(double thuc, double ao)
{
 t=thuc;
 a=ao;
}
void SP::nhap()
{
 cout<<"nhap phan thuc: ";
 cin>>t;
 cout<<"nhap phan ao";
 cin>>a;
}
void SP::xuat()const
{
 cout<<t<<" + "<<a<<"i"<<endl;
}
double SP::tinhchuan()
{
 return sqrt(t*t+a*a);
}
SP SP::cong(SP p)
{
 SP q;
 q.t=this->t+p.t;
 q.a=this->a+p.a;
return q;
}
void SP::setthuc(double thuc)
{
 t=thuc;
}
void SP::setao(double ao)
{
 a=ao;
}
double SP::getthuc()
{
 return t;
}
double SP::getao()
{
 return a;
}

void main()
{
 SP s1;
 s1.xuat();
 s1.setthuc(1);
 s1.setao(2);
 s1.xuat();
 SP s2(3,4);
 s2.xuat();
 SP st;
 st=s1.cong(s2);
 st.xuat();
 double db=st.tinhchuan();
 cout<<db<<endl;
}

#include <iostream>
#include<cstring>
using namespace std;


class stringclass{
private:
 char * p;
public:
 int len;
 stringclass()
 {
  cout<<"default";
 }
 stringclass(const stringclass & ExistingObject)
 {
  cout<<"copy constructor    ";
  p= new char[ExistingObject.len+1];
  len=ExistingObject.len;
  strcpy(p,ExistingObject.p);
 }
 stringclass(char * pr)
 {
  cout<<"purum constructor:  ";
  len=strlen(pr);
  p=new char[len+1];
  if(p!=NULL)
  strcpy(p,pr);
 }
 ~stringclass()
 {
  cout<<"delete"<<endl;
  if(p!=NULL)
  delete p;
 }
 void show()
 {
  cout<<p<<"    len:= "<<len<<endl;
 }
};
 
int main()
{
 stringclass s1("abcdef");
 s1.show();
 stringclass s2();
 stringclass s3(s1);
 s3.show();

 return 0;
}