C++ Program to swap numbers using class

#include<iostream.h>
#include<conio.h>
class swap       //Class name
{
int a,b;
public:
void getdata();    //Declaration
void swapv();
void display();
};
void swap::getdata()          //Member function definition
{
cout<<"Enter two numbers:";
cin>>a>>b;
}
void swap::swapv()
{
 a=a+b;
 b=a-b;
 a=a-b;
 }
 void swap::display()
 {
 cout<<"\na="<<a<<"\nb="<<b;
 }
 main()                        //Main program
 {
 clrscr();
 swap s;
 s.getdata();                  //Accessing getdta and display
 cout<<"\nBefore swap:";
 s.display();
 s.swapv();
 cout<<"\nAfter swap:";
 s.display();
 getch();
 return 0;
 }