Basic OOPS ques 7

#include<iostream.h>
#include<conio.h>
class complexnum
{int real,imaginary;
public:
void readdata();
void display();
complexnum addcomplex(complexnum);
complexnum subcomplex(complexnum);
}c1,c2;
void complexnum::readdata()
{cout<<"enter real \timaginary";
cin>>real>>imaginary;
}
void complexnum::display()
{cout<<"real "<<real<<" imaginary "<<imaginary<<endl;
}
complexnum complexnum::addcomplex(complexnum c2)
{ complexnum c5;
c5.real=real+c2.real;
c5.imaginary=imaginary+c2.imaginary;
return c5;}
complexnum complexnum::subcomplex(complexnum c2)
{complexnum c4;
c4.real=real-c2.real;
c4.imaginary=imaginary-c2.imaginary;
return c4;
}
void main()
{clrscr();
c1.readdata();
c2.readdata();
c1.display();
c2.display();
complexnum c4,c5;
c5=c1.addcomplex(c2);
c4=c1.subcomplex(c2);
cout<<"c4=";
c4.display();
cout<<"c5=";
c5.display();
getch();
}